# Greetings all! New to the board, new to the old GTO



## Beef Supreme (Jan 11, 2021)

Hello gentlemen. I’ve been lurking for a bit but decided to join as I plan on sticking with the GTO for a while.
So some background....
I previously owned a 2006 GTO. Had ported/polished heads, cam (236/240 with .610 lift on a 111Lsa), intake, fuel injectors, custom made cold air kit (actually registered ambient temps), long tube headers, wheels, drag bags, dash-hawk engine monitor, etc etc.
Made roughly 480-490 at the wheels. Planned on procharging it, but it never work out.

Fast forward 10 years and now I have a 1971 gto convertible. 400CI engine. New rods and pistons but original crank (I believe). Bored over slightly. Heads had valve job and whatever else was needed to run on unleaded, but no port work. Has long tube headers and exhaust. Has what was called a “correction cam” put in. Has a 3 speed auto which has been rebuilt. It has an edelbrock carb, but I have the original Q-jet in perfect working order in a box, ready to be swapped back on.
Car is all original. Runs like a champ. Starts right up, has a nasty looping idle which I love, shifts hard and chirps gears.
As many men before me, I want more. There are changes I want to make for aesthetics, and others for power. I’ve been searching and reading, but figured I should join and just ask.
I need to fix the AC. It’s all original still but doesn’t work, not sure what’s wrong with it. Anybody know a
Power wise, I debated swapping an LS engine in. Sacrilege I know. But I was given pause by a few things...
-If I swap an LS in, do I need to swap the trans? I mean it would make sense to swap trans and have more than 3 gears, but an engine/trans swap is getting pricey. 

the current engine runs great, and already has headers, work done. Do I want to pull it?
the car is original, not a clone or anything. I don’t want to shit all over the value.

So I’ve been doing some reading and I keep seeing KRE aluminum D-port heads mentioned.
So my questions....
How much power would I pick up with a set of KRE ported (for the street) heads? I’m trying to see if I can justify spending $2500 plus install costs. Are we talking 25hp, 60hp?
Is it worth the cost, or should I drop in a LS or big block (if they bolt up to the t
If I swap heads, would a higher lift cam really be worth it as well? What kind of power over stock are we talking with a head/cam swap over stock? Anybody got say I results with this head swap?
As for the trans.... more than 3 gears would be great. More performance, and the engine wouldn’t be screaming doing 80mph on the highway. But as said, the trans runs flawlessly. Would a gear vendors over drive be a good solution?

Im fairly certain you guys would all agree to put the q-jet back on 😁

Im apologize for the 20 questions. I am not very familiar with the older engines/cars from a technical standpoint. I’ve always loved them, but this isn’t first first-hand experience. I want to come up with a solid game plan and execute it. I don’t intend to keep switching directions and redoing work. So I’m trying to see what my results would look like with the heads or heads and cam and see if that satisfies me, or if I will be left unfulfilled.

last question... any of you guys in south Florida? I need a good shop I can trust down here. I don’t want some ******* “working” on my new baby and half adding it, or learning about Pontiac’s on mine.

Thank you gentlemen for your time. I’ve enjoyed reading through this board for a while and seeing your cars and the work you’ve done.


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## pontrc (Mar 18, 2020)

Welcome Beef, I would keep her the way it is . Still kind of cringe about ls engines in GTOs, I’m still mad at GM for the way they treated Pontiac and I refuse to put any gm corporate logo on my car. The 200 4R is a good transmission upgrade as it has the “ BOP” bell housing pattern


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## Beef Supreme (Jan 11, 2021)

pontrc said:


> Welcome Beef, I would keep her the way it is . Still kind of cringe about ls engines in GTOs, I’m still mad at GM for the way they treated Pontiac and I refuse to put any gm corporate logo on my car. The 200 4R is a good transmission upgrade as it has the “ BOP” bell housing pattern


Thank you sir! Good to be here.
I will likely not swap motors.
But absolutely want some more ooomph out of this motor, so I’m debating the head swap or head/cam swap.


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## armyadarkness (Dec 7, 2020)

As for the LS swap, I have some weird views on future GTO collectors... I think that millenials will probably prfer the LS engines, so I don't think that an LS swap will hurt value as much (as I'm sure most others do) as the years go on. That being said, if you're looking to do an LS swap GTO, then you'd likely be better off buying a GTO that's not original and has far less value, for your base car. Not much point in chopping an original, because that adds to value.

As for the carb, yes the entire GM internet will tell you to use a Quadrajet, but if you're like me, you will (spend years and...) not find a core that either of the "two" popular, reputable builders will touch. Or, you will and it'll cost $1500. I'm not sure how you know that the original Qjet works perfectly, but if so, then go with it. I personally love the Edelbrocks and I just put a new AVS2 800 on my 400.

I have a 67 and I just made a post a few days back, about keeping an original GTO appearing all original, but yet updating the driveability and reliability.

With engine that you have and the parts that are available for it, you can make as much power and reliability as you like. What gears are in the car and what heads are on it? You should be able to make big power with that car, without changing too much. Especially if they already worked on the engine.

Get the right carb, great spark, and a dual exhaust and you should spin the tires off the wheels. It won't hook up and go like the 2006... It's more of a tire destroyer.


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## Beef Supreme (Jan 11, 2021)

armyadarkness said:


> As for the LS swap, I have some weird views on future GTO collectors... I think that millenials will probably prfer the LS engines, so I don't think that an LS swap will hurt value as much (as I'm sure most others do) as the years go on. That being said, if you're looking to do an LS swap GTO, then you'd likely be better off buying a GTO that's not original and has far less value, for your base car. Not much point in chopping an original, because that adds to value.
> 
> As for the carb, yes the entire GM internet will tell you to use a Quadrajet, but if you're like me, you will (spend years and...) not find a core that either of the "two" popular, reputable builders will touch. Or, you will and it'll cost $1500. I'm not sure how you know that the original Qjet works perfectly, but if so, then go with it. I personally love the Edelbrocks and I just put a new AVS2 800 on my 400.
> 
> ...


Thank you. As for how I know the carb works... it was my uncles car and the carb was the original on there previously. Said it works just fine and encouraged me to put it back on. 
already got long tubes and exhaust. As far as I know, my bottle neck is the heads. I don’t know what heads are on there, I’m assuming the stock 1971 heads for the 400CI engine. I can check and look.

I agree with what you said about the LS swap, that’s why I likely won’t go that direction. Just curious how much bang for the buck I’ll get for a head swap or head/can swap.


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## armyadarkness (Dec 7, 2020)

Beef Supreme said:


> Thank you. As for how I know the carb works... it was my uncles car and the carb was the original on there previously. Said it works just fine and encouraged me to put it back on.
> already got long tubes and exhaust. As far as I know, my bottle neck is the heads. I don’t know what heads are on there, I’m assuming the stock 1971 heads for the 400CI engine. I can check and look.
> 
> I agree with what you said about the LS swap, that’s why I likely won’t go that direction. Just curious how much bang for the buck I’ll get for a head swap or head/can swap.


Heads should have a number on them. Pontiac had plenty of good heads, and with know-how, even some of the crappy ones could be jazzed up. 

I assume that you're not happy with the power now? If it's chirping tires and has a cam, I think that "someone" would've long since paid attention to the heads, so you could be in luck. 

Before I considered swapping heads, I'd be sure that the spark was the best going (un-worn distributor with HEI or upgraded module, big coil, big gap on the plugs, 8mm wires, new cap and rotor), and that the carb was jetted right (my preferred method is to install and AEM air/ fuel gauge, but you can also either read the plugs or have it dyno's, and that the timing was perfect with max advance. If any of those things are off, you could be losing massive horse power.

If in fact the Qjet has survived 40 years, then by all means, go for it. Mine looked awesome and was "supposedly" original... however, it was actually off a 1975 Chevy truck. It leaked air at the throttle plates and so it idled too high. Qjets are awesome, but a bad or untuned one is much wosre than a setup Edelbrock.


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## armyadarkness (Dec 7, 2020)

BTW... What size carb is on it? If it's less than a 750, then you're going to be fighting uphill.


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## Beef Supreme (Jan 11, 2021)

armyadarkness said:


> Heads should have a number on them. Pontiac had plenty of good heads, and with know-how, even some of the crappy ones could be jazzed up.
> 
> I assume that you're not happy with the power now? If it's chirping tires and has a cam, I think that "someone" would've long since paid attention to the heads, so you could be in luck.
> 
> ...


Thank you for the advice. I’ll check to see what the heads were stamped.
As for the spark, timing, etc... I have no idea. I also don’t know how to check this, neva been done befo’.
Sounds like I need to find a good shop down here or somebody who knows what they are doing.
Anybody in south Florida?


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## Jetzster (Jan 18, 2020)

Welcome to the Forum Beef,super nice one👍


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## Olds455 (Mar 31, 2014)

Congrats on the purchase! I don't like others telling me how to build my car ('65 GTO with an OLDSMOBILE 455 in it - that way when my dad bought it in 1985). But, since this is all original, I'd try to keep it as close as possible. Armyadarkness' recommendations are spot on. Throw on some headers, maybe swap to aluminum intake and heads. You can improve driveability slightly with a Holley Sniper EFI now that they make a Qjet-compatible throttle body. That will keep the came lope and improve cold start. I haven't seen anything definitive on fuel economy improvements, but they do seem to improve slightly.


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## PontiacJim (Dec 29, 2012)

Beef Supreme said:


> Thank you for the advice. I’ll check to see what the heads were stamped.
> As for the spark, timing, etc... I have no idea. I also don’t know how to check this, neva been done befo’.
> Sounds like I need to find a good shop down here or somebody who knows what they are doing.
> Anybody in south Florida?


There is a lot more to it than just slapping heads on the car and shooting for more HP.

You want to match your parts. "Just" adding heads could be an expensive disappointment. Most all aluminum heads will flow more CFM's out of the box than a set of prepped iron heads. But adding more CFM's by itself means the bottom RPM range won't see much flow velocity and bog out with reduced power, and then they will work in the upper RPM's which means you have to run your engine harder in the upper RPM's to take advantage of the increased flow.

First off, what octane gas are you willing to work with? Pump gas, pump gas + octane booster, or high octane race gas? Your choice is all about compression and it is the engine's compression you want to match your top end components to. Your engine, if stock, will have flat top pistons as Pontiac do. It is the head combustion size, ie CC's of the chamber, that dictate compression. So knowing what $octane you are willing to run can dictate what size the chamber CC's are - this is why they list the different CC's as options on the aluminum heads.


Once you have decided what compression you plan on going with, based on octane requirement & head CC's, then you can start to look at a cam choice. However, bigger is not always better. You have to take into consideration the engine's operating range you think you will most likely see. With that, you also have to take into consideration the torque converter stall, transmission gearing, and rear axle gearing - again, you want to match components or spend money with disappointing results and convince yourself that you just should have gone with the LS swap.

Then you want to select an intake & carb to match the cam & heads. Why choose an intake that restricts the incoming air flow which in turn chokes off the added benefit of those great CFM flowing heads and a cam that compliments the heads? Or even too small of a carb. Again, you gotta' match ALL your parts, not just slap on heads and then look to improve the HP 10 fold.

Keep in mind that cast iron connecting rods and cast pistons will also limit RPM's, and bigger CFM's means higher RPM's and you don't want things coming apart. One reason a stroker kit that turns the 400CI into a 461CI is the best bang for your buck - forged piston, rods, stroker crank and more cubic inches to take advantage of additional CFM's and still keep RPM's reasonable.

So don't take any of this the wrong way, but know that with a Pontiac engine that you want to sit down and set your goals as to what you want out of the car, and then what kind of HP/TQ you want from the engine to make this happen. But, just like an LS swap, you can put more HP/TQ in the engine bay, but then you are going to find all the factory weaknesses from the flywheel back. So in setting up a budget for the engine build, you want to be honest and include a budget to upgrade the rest of the drivetrain to handle the additional HP/TQ, or get a membership with AAA for the tow home and keep a bucket in the trunk to pick up the pieces while waiting for the tow. 

Don't think you can't pull HP/TQ out of a Pontiac and get dependability. EFI systems seem to be a nice improvement that works for those who want to get away from a carb. Electronic ignition is just an order form away at Summit, Jegs, or any other supplier. It doesn't take a computer controlled engine to have the modern upgrades added to a Pontiac that will make it as dependable as any LS, but less complicated should the computer controls crap out.

That said, you can take a little time to learn about Pontiac performance and how a good engine is built, or skip the learning curve and just go LS swap. Will it hurt value? Probably not, might actually increase value, but are you looking to sell it? If so, pull the engine/trans and tuck it away in a corner and offer it to the next buyer who may or may not want to return the car back to original. So as long as you do the swap "cleanly" and don't hack the car up where it incurs damage that can't be reversed, do what your gut tells you as it is your car. We don't tell you not to do it because it is your car, but many of us are old school Pontiac people and we prefer a Pontiac engine in a Pontiac body.


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## Beef Supreme (Jan 11, 2021)

PontiacJim said:


> There is a lot more to it than just slapping heads on the car and shooting for more HP.
> 
> You want to match your parts. "Just" adding heads could be an expensive disappointment. Most all aluminum heads will flow more CFM's out of the box than a set of prepped iron heads. But adding more CFM's by itself means the bottom RPM range won't see much flow velocity and bog out with reduced power, and then they will work in the upper RPM's which means you have to run your engine harder in the upper RPM's to take advantage of the increased flow.
> 
> ...


thank you for the response.
While I am totally new to the classic GTO, I’m not completely new to the performance scene. I completely understand what you are talking about regarding having components that match, RPM ranges, too big of a cam, etc.
400CI is a decent sized motor, so I was hoping to squeeze more power out of it and I was under the impression that the stock heads essentially suck.
The car already has long tube headers and I do believe forged rods and pistons. I’ll double check though. Already has a cam, which I will check, but I’m willing to replace that if the heads dictate it.
Transmission has already been built up as well if I recall correctly. I have pretty much all the receipts and paperwork for items ordered that has been done with the car.
It was my understanding that the stock Q-jet and intake manifold were pretty damn good, and not a restriction if you put better flowing heads on. Correct me if I’m wrong.
It was my understanding that the stock heads in a 71 GTO bottle neck the performance rather significantly, hence my desire to replace them. I can check on the castings, and will do so to give you guys a better picture.
I understand just dropping on big ol’ hogged out ported heads is not the way to go as it moves the power up much higher in the RPM range and the slow port velocity kills low rpm torque. It’s a street car, and I don’t really need power at 6000+ rpms. Same with the cam. Not looking to put a big cam with big duration in there, as I want my low and midrange power. But with new heads, I figured they would be able to use a cam with a higher lift.

For fuel, I run 93 octane.

im sure I’ve got lots of reading here to do, and I appreciate all of your input. My next mission is to find a south Florida mechanic/shop that I can trust to work on it.
I would like to have the timing and ignition checked as was posted earlier. And for work in the future.

Let me dig into my paperwork and see what else I got, info wise.


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## Beef Supreme (Jan 11, 2021)

So I’m digging through paperwork. Can’t find the cam info as to what cam was installed. However I did find the sheet listing the work that has been done to the heads and block.

for an added treat, I have the 1988 “high-performance Pontiac” magazine that featured an article about my car. Check it out.


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## armyadarkness (Dec 7, 2020)

Are you looking to learn how to do all of this on your own? You've repeatedly mentioned "finding a shop" in South Fla, and if a shop is capable of performing the work, they'll likely be able to make power and tuning recommendations as well. As for finding one, Google, the forums, and Craigslist should do it. I know that Craigslist can be a slippery slope, but if there's an old school/ backyard Pontiac guru there, that's where you'll find him. You can also look to "buy" GTO parts on CL in your area. Anyone with parts to sell, probably knows about GTO's and who works on them.

Timing is a big deal and if it was simply set by the sticker on the car, then it's probably not optimal. If you're willing to work on it yourself, there's help right here.


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## Beef Supreme (Jan 11, 2021)

armyadarkness said:


> Are you looking to learn how to do all of this on your own? You've repeatedly mentioned "finding a shop" in South Fla, and if a shop is capable of performing the work, they'll likely be able to make power and tuning recommendations as well. As for finding one, Google, the forums, and Craigslist should do it. I know that Craigslist can be a slippery slope, but if there's an old school/ backyard Pontiac guru there, that's where you'll find him. You can also look to "buy" GTO parts on CL in your area. Anyone with parts to sell, probably knows about GTO's and who works on them.
> 
> Timing is a big deal and if it was simply set by the sticker on the car, then it's probably not optimal. If you're willing to work on it yourself, there's help right here.


Im looking for both really.
I absolutely want to learn how to do things myself on this car. That’s a goal, and this board will certainly help. I’m going to try and read up on how to swap carbs, and how to check/adjust the timing.
And yes, I certainly want to find a good shop(s). There are certainly things I either can’t do because I lack the knowledge or don’t have the tools or both. And really, at some point stuff goes wrong and needs to be fixed, and I’d like it done properly.

I really appreciate the help you guys have provided. I’m gonna search up how to check/adjust timing so I can check that this weekend.


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## armyadarkness (Dec 7, 2020)

Beef Supreme said:


> Im looking for both really.
> I absolutely want to learn how to do things myself on this car. That’s a goal, and this board will certainly help. I’m going to try and read up on how to swap carbs, and how to check/adjust the timing.
> And yes, I certainly want to find a good shop(s). There are certainly things I either can’t do because I lack the knowledge or don’t have the tools or both. And really, at some point stuff goes wrong and needs to be fixed, and I’d like it done properly.
> 
> I really appreciate the help you guys have provided. I’m gonna search up how to check/adjust timing so I can check that this weekend.


Doing it yourself is the way to go, and if you have basic tool skills, you can do it... So long as you have good information.

I've been working on cars for several decades, but I always avoided a lot of engine stuff, so I'm learning it all now myself. So long as you already understand the theory and science behind it all, then all you really need is determination and a few specifications.

Start writing down the things that you want to do, then start grouping them and prioritizing. I tend to do several things at once, and that's not usually the best way... It tends to make things hectic, however I do get more done faster. Once you have you list, present it here and then you'll get help with the order of things.

For example, don't bother messing with the carb until the ignition is done. If you're not burning the fuel, then there's no point in adding or subtracting any, yet. Get youself a timing light, preferably an adjustable one, hook it up and see where you're at. If they previously set it according to the emissions label, then you'll get some seat of the pants improvements by advancing it, but no point in "going there" until you're ready to tackle it.


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## armyadarkness (Dec 7, 2020)

This is by Miami...




__





Specialized in Pontiac Trans Am






transamflorida.com


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## Beef Supreme (Jan 11, 2021)

armyadarkness said:


> Doing it yourself is the way to go, and if you have basic tool skills, you can do it... So long as you have good information.
> 
> I've been working on cars for several decades, but I always avoided a lot of engine stuff, so I'm learning it all now myself. So long as you already understand the theory and science behind it all, then all you really need is determination and a few specifications.
> 
> ...


Nice. Sounds good. So start with the ignition you say. I’ll do some reading regarding how to check if it’s working up to snuff. I’ll also take some pics of under the hood to see what has already been replaced. I’ll also grab myself a timing light.
If all is well, I’ll drop her carb on.

I have a feeling things are in working order, but I’ll check.

I really appreciate all your help and suggestions. Thank you much!


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## armyadarkness (Dec 7, 2020)

Beef Supreme said:


> Nice. Sounds good. So start with the ignition you say. I’ll do some reading regarding how to check if it’s working up to snuff. I’ll also take some pics of under the hood to see what has already been replaced. I’ll also grab myself a timing light.
> If all is well, I’ll drop her carb on.
> 
> I have a feeling things are in working order, but I’ll check.
> ...


Yes ignition is the place to start. Verify that the timing is where it should be, which most here will say is as close to 36 degrees as you can get, without engine knock. If you've never checked timing before, the procedure can't really be simplified here, but there are numerous papers on the topic. Google "Lars timing papers". He's a member here and also an activist in the Vette world, which is where I met him. The procedure and specifications are the same for a GTO or a Vette. read up on it, and then ask questions.

If the timing is good, check to be sure that the plugs are good, gapped right, and firing, if so, then the wires cap and rotor are good, too. Without seeing what you have, it's tough to say what you should improve. I had a 79 Trans Am with an Olds 403. Stock, it didn't spin the tires. With an Accel Super Coil, it spun both tires and chirpped 2nd. 

So if you're looking for more power, then improve your ignition as best you can afford, after that, then your carb will show it's true colors.


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## Beef Supreme (Jan 11, 2021)

armyadarkness said:


> Yes ignition is the place to start. Verify that the timing is where it should be, which most here will say is as close to 36 degrees as you can get, without engine knock. If you've never checked timing before, the procedure can't really be simplified here, but there are numerous papers on the topic. Google "Lars timing papers". He's a member here and also an activist in the Vette world, which is where I met him. The procedure and specifications are the same for a GTO or a Vette. read up on it, and then ask questions.
> 
> If the timing is good, check to be sure that the plugs are good, gapped right, and firing, if so, then the wires cap and rotor are good, too. Without seeing what you have, it's tough to say what you should improve. I had a 79 Trans Am with an Olds 403. Stock, it didn't spin the tires. With an Accel Super Coil, it spun both tires and chirpped 2nd.
> 
> So if you're looking for more power, then improve your ignition as best you can afford, after that, then your carb will show it's true colors.





http://outintheshop.com/faq/Lars%20timing%20.pdf



I pulled up that. Reading it, I’m lost as far as how to do this stuff. I don’t even know how to use a timing light. I’m sure you guys are laughing, I kinda am. Perhaps I can youtube some of it. Would also like to check my ignition function, spark plugs, make sure I’m getting a strong spark, etc.

well, my journey has just begun it would seem. Hopefully I can meet somebody local to me who knows how to do this kinda stuff, and we can play with the cars together. That’s good times.
It’s really amazing just how different this car is under the hood as compared with my 2006 GTO. Completely different animals. I gotta say though, these older cars are awesome.


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## armyadarkness (Dec 7, 2020)

Beef Supreme said:


> http://outintheshop.com/faq/Lars%20timing%20.pdf
> 
> 
> 
> ...


No one would laugh. Most people don't have enough interest to ask. You've already made the big leap. More to come tomorrow. You'll get it and people will help.


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## Jetzster (Jan 18, 2020)

Beef Supreme said:


> http://outintheshop.com/faq/Lars%20timing%20.pdf
> 
> 
> Perhaps I can youtube some of it.
> well, my journey has just begun it would seem. I gotta say though, these older cars are awesome.


That’s it Beef
Utube ,and the guys here, will give you the knowledge ,
just take on one thing on there at a time
and you’ll be fine , and your knowledge base
Will expand quickly , lookin good😎 man
They are so awesome, there’s nothin else like this


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## Atarchus (Aug 4, 2020)

You sound similar to me! I bought a 2006 GTO brand new back in the day and now have a 1970 GTO convertible! I did a full motor rebuild on mine, 400 block bored/stroked to 461, aluminum heads, cam, Pro Flo 4 multi-port fuel injection... etc. Butler performance provided the engine recipe and parts and it put out 500hp/550tq on the engine dyno. It's just the right amount of power to make driving on the street exciting. I'm also in the process of a 200-4R conversion, that's still in the works. No matter what you do, they are fun cars!


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## Beef Supreme (Jan 11, 2021)

Atarchus said:


> You sound similar to me! I bought a 2006 GTO brand new back in the day and now have a 1970 GTO convertible! I did a full motor rebuild on mine, 400 block bored/stroked to 461, aluminum heads, cam, Pro Flo 4 multi-port fuel injection... etc. Butler performance provided the engine recipe and parts and it put out 500hp/550tq on the engine dyno. It's just the right amount of power to make driving on the street exciting. I'm also in the process of a 200-4R conversion, that's still in the works. No matter what you do, they are fun cars!


Those are great numbers. Congrats on your car.
I’m really curious as to the current tune of my motor now. These guys got me thinking about the ignition, timing, etc.
I’m gonna have to check that out.


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## PontiacJim (Dec 29, 2012)

Beef Supreme said:


> Those are great numbers. Congrats on your car.
> I’m really curious as to the current tune of my motor now. These guys got me thinking about the ignition, timing, etc.
> I’m gonna have to check that out.


Working on your car is not difficult if you have some mechanical skills. They are really quite simple once you know the aspects of how to work them.

Many of us here can walk you through it if that is what you want and you can decide what you feel you can tackle and what you want to leave to a shop. It is still a wise idea to know what is going on so you can be on the same page as the shop mechanic you choose and know if you are getting facts or hosed.

Plenty of info on timing if you use the search function on this site. Timing lights are easy enough to use and can be a good tool to add to the tool box. If you do, you want to get what is called a "dial back" timing light which has the ability for adjustments used in timing the engine.

You might consider doing the trans/rear axle as an upgrade rather than to dig into the engine right now. You might want to go with the OD automatic and a set of rear gears like 3.55's which would really get the car moving in the lower gears and have the engine loafing at 70 MPH. The acceleration alone will be as adding more HP without touching the engine.

You were thinking OD trans anyway, and I might tackle that first, along with better gearing. My guess is you may have 3.08's, or even 2.78's as factory gearing? Not sure when the 8.5 rear end was installed, but have read it may have been used on some 1971 cars, but for sure 1972. The 8.5 rear end is about as good as any 12-bolt and can be made to handle a bunch of HP/TQ with a few upgrades. So you might try to see what you have. The 10-bolt 8.2 is not a favorable rear end for bigger HP/TQ and sticky tires.


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## Atarchus (Aug 4, 2020)

Beef Supreme said:


> Those are great numbers. Congrats on your car.
> I’m really curious as to the current tune of my motor now. These guys got me thinking about the ignition, timing, etc.
> I’m gonna have to check that out.


I've been learning about timing since installing the Pro Flo 4 kit. Luckily it's all computer controlled so making adjustments is VERY easy. I initially had 15 degrees of initial timing and 10 degrees of vacuum advance. I increased my initial timing to 20 degrees which made it much more responsive and got rid of the stumble from a dead stop, but with 20 initial and 10 vacuum advance, it started missing during part throttle acceleration. I lowered the vacuum advance to 5 and it seems to have solved that issue. It's certainly a learning experience, just know that the more initial timing you have the less vacuum advance you can run.


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## Beef Supreme (Jan 11, 2021)

PontiacJim said:


> Working on your car is not difficult if you have some mechanical skills. They are really quite simple once you know the aspects of how to work them.
> 
> Many of us here can walk you through it if that is what you want and you can decide what you feel you can tackle and what you want to leave to a shop. It is still a wise idea to know what is going on so you can be on the same page as the shop mechanic you choose and know if you are getting facts or hosed.
> 
> ...


So you suggest swapping out the trans entirely?
As for to rear, I know the car does not have a posi rear end. That needs to be addressed.
How can I tell the type of rear (8.5, 12 bolt, etc)? Is it stamped on the diff cover?


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## Atarchus (Aug 4, 2020)

Beef Supreme said:


> So you suggest swapping out the trans entirely?
> As for to rear, I know the car does not have a posi rear end. That needs to be addressed.
> How can I tell the type of rear (8.5, 12 bolt, etc)? Is it stamped on the diff cover?


Counting the bolts will tell you if it's a 10 or 12. As far as 8.2 or 8.5 there are many references with pictures if you Google. However, if your car has been worked on/modified/restored previously it can be hard to tell if it's a 8.2 or 8.5 because afaik most cases/covers are interchangeable and could be mixes/matched when doing a restoration.


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## armyadarkness (Dec 7, 2020)

PontiacJim said:


> Working on your car is not difficult if you have some mechanical skills. They are really quite simple once you know the aspects of how to work them.
> 
> Many of us here can walk you through it if that is what you want and you can decide what you feel you can tackle and what you want to leave to a shop. It is still a wise idea to know what is going on so you can be on the same page as the shop mechanic you choose and know if you are getting facts or hosed.
> 
> ...


Agreed. Jim has been helping me through my tuning and to wring out the previous owners neglect. Last night I welded up the exhaust and took it for a test drive. 

In a weakened state of tune (crummy wires, valves need adjusting, carb not jetted) with a mild 400; While cruising at 50mph, I nailed it and the tires (new BFG radials) almost broke free when it down shifted. Then it tore off and the TH400 chirpped hard when it shifted again.

Meanwhile... Two days ago, the car didn't even downshift at all, because the switch wasn't set right. Persistence is everything here.


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## armyadarkness (Dec 7, 2020)

Beef Supreme said:


> So you suggest swapping out the trans entirely?
> As for to rear, I know the car does not have a posi rear end. That needs to be addressed.
> How can I tell the type of rear (8.5, 12 bolt, etc)? Is it stamped on the diff cover?


Google BOP diff gasket and look at the images. Way different than chevy.


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## Beef Supreme (Jan 11, 2021)

armyadarkness said:


> Agreed. Jim has been helping me through my tuning and to wring out the previous owners neglect. Last night I welded up the exhaust and took it for a test drive.
> 
> In a weakened state of tune (crummy wires, valves need adjusting, carb not jetted) with a mild 400; While cruising at 50mph, I nailed it and the tires (new BFG radials) almost broke free when it down shifted. Then it tore off and the TH400 chirpped hard when it shifted again.
> 
> Meanwhile... Two days ago, the car didn't even downshift at all, because the switch wasn't set right. Persistence is everything here.


See that right there is something else I wanted to address.
The car doesn’t seem to down shift properly.
If I was doing 50 and nail it... no down shift.
It accelerates, but that more a matter of the large torque production.
I gotta see what’s up with that, or if it’s in my head being this is my first fence with a 3 speed car from the 1970’s.

I really need to go though this car. It starts great, cruises, etc.
however, it has been sitting in a garage for about 10 years with maybe a couple weekend outings a year. I have a feeling it’s way out of tune. Granted it has no catalytic converters and has a looney cam (overlap) but it smells rich at idle. I think I’m wasting a lot of fuel.
I almost don’t know where to begin. I guess at the ignition/spark system as previously mentioned, right?


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## Jim K (Nov 17, 2020)

Welcome to the forum! Lots of knowledgeable folks on here.. Already some good and sage advice.. Bottom line, it's your car so build the motor or swap it as you see fit. (although I am one of those guys that cringes when an LS swap is mentioned). Yeah, an old school motor is far different than todays variety, but you can do so many different builds with an old school motor. That's half the fun!
As Pontiac Jim said, you have to match your parts up.. But before hand, you have to have a clear direction of how you plan on driving your car and what RPM ranges you plan to operate in. Case in point- While long tube headers have been around for decades and are usually one of the first upgrades to be made, you don't start to see the benefits of them until getting into the 5,000+ RPM range. If you don't plan on being in that RPM range on a frequent basis, then maybe the factory performance exhaust manifolds pared with larger diameter exhaust piping is the better way to go, or "shorty" headers. 
Deciding how you will drive will determine your path forward. Remember, doing one change or upgrade affects other components.
As for the original motor, the 71 400 was rated at 300 HP at the flywheel. The original heads were casting #96 and gave only about 8.2:1 static compression ratio. 1971 was the first year of "hard seated" heads due to the feds new rules. While I am not sure what the term "correction cam" means, the original was the Pontiac "P" cam. There are a few good web sites dedicated to Pontiac performance. One of my "go-to" sites is www.wallaceracing.com they have a page full of calculators that come in handy when planning and building your motor/drive train.
Welcome aboard and don't hesitate to start a thread of questions as your journey progresses!


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## Beef Supreme (Jan 11, 2021)

Jim K said:


> Welcome to the forum! Lots of knowledgeable folks on here.. Already some good and sage advice.. Bottom line, it's your car so build the motor or swap it as you see fit. (although I am one of those guys that cringes when an LS swap is mentioned). Yeah, an old school motor is far different than todays variety, but you can do so many different builds with an old school motor. That's half the fun!
> As Pontiac Jim said, you have to match your parts up.. But before hand, you have to have a clear direction of how you plan on driving your car and what RPM ranges you plan to operate in. Case in point- While long tube headers have been around for decades and are usually one of the first upgrades to be made, you don't start to see the benefits of them until getting into the 5,000+ RPM range. If you don't plan on being in that RPM range on a frequent basis, then maybe the factory performance exhaust manifolds pared with larger diameter exhaust piping is the better way to go, or "shorty" headers.
> Deciding how you will drive will determine your path forward. Remember, doing one change or upgrade affects other components.
> As for the original motor, the 71 400 was rated at 300 HP at the flywheel. The original heads were casting #96 and gave only about 8.2:1 static compression ratio. 1971 was the first year of "hard seated" heads due to the feds new rules. While I am not sure what the term "correction cam" means, the original was the Pontiac "P" cam. There are a few good web sites dedicated to Pontiac performance. One of my "go-to" sites is www.wallaceracing.com they have a page full of calculators that come in handy when planning and building your motor/drive train.
> Welcome aboard and don't hesitate to start a thread of questions as your journey progresses!


Thank you very much.
I’m really liking this board very much, you guys are great. And yes, some great advice. I didn’t even think to check the spark/ignition and timing. I’m used to that being computer controlled.
I need to check that, along with the shifting.
Tough part is my tach doesn’t work, so I can’t see where my rom’s are at, and this motor sounds so different from an LS I don’t think I can guesstimate accurately.
As for the heads, they have been worked on. See below...


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## PontiacJim (Dec 29, 2012)

Beef Supreme said:


> So you suggest swapping out the trans entirely?
> As for to rear, I know the car does not have a posi rear end. That needs to be addressed.
> How can I tell the type of rear (8.5, 12 bolt, etc)? Is it stamped on the diff cover?


Why not? You were planning on upgrading at some point in the future, right? Just make sure it has the Pontiac/Chevy bolt patterns so if you go LS you can use it. You will have to adapt the shifter, but I recall there is a kit for that if you search for it online.

Do a search on the site up in the search box for 8.5 rear end. Plenty input on these and how to ID them from the 8.2 rear. They appear similar until you know what to look for.


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## WalterClark (Jun 20, 2020)

Beef Supreme said:


> Hello gentlemen. I’ve been lurking for a bit but decided to join as I plan on sticking with the GTO for a while.
> So some background....
> I previously owned a 2006 GTO. Had ported/polished heads, cam (236/240 with .610 lift on a 111Lsa), intake, fuel injectors, custom made cold air kit (actually registered ambient temps), long tube headers, wheels, drag bags, dash-hawk engine monitor, etc etc.
> Made roughly 480-490 at the wheels. Planned on procharging it, but it never work out.
> ...


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## WalterClark (Jun 20, 2020)

Where are you located in south Florida ?


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## Beef Supreme (Jan 11, 2021)

WalterClark said:


> Where are you located in south Florida ?


Wellington.
Palm beach county.


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