# 389 Options?



## renorealtors (Apr 7, 2018)

Hi I have started a restoration on a 1965 GTO. As I am looking around the internet I find the 389 won't run on pump gas? Also the motors valves are not set up for todays fuels?? Can any one ring in on this. I will know if the thing even runs in a few weeks but want to be ahead of it. I will slso:grin2: know the facts on # matching soon so if it is not I may just convert to a LS or some other option but wanted to keep it original. Since it will get driven here in Reno Nevada for shows and Hot August Nights it needs to run on premium?


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## bigD (Jul 21, 2016)

You have lots of Pontiac options. The worst thing you could do is go with a Chevy engine, IMO.

If you wanna use a 389 block, you can set it up with the correct pistons to provide the CR you want, with the heads you wanna use. 

If you wanna use 389 heads, you can have 'em rebuilt, with one piece stainless valves, hardened valve seat inserts, and screw-in studs, by somebody with expertise & experience doing Pontiac heads correctly. Many have reported that it costs in the neighborhood of $1000 to have a set of the older press-in stud Pontiac heads done correctly. 

https://butlerperformance.com/c-1234874-engine-components-internal-pistons-dss-forged-pistons.html

If you wanna use later model 350 or 400 heads, you can have the 389 short block built with pistons which have valve reliefs in the correct location for use with later model heads. 

https://butlerperformance.com/i-244...4-080-or-4-100-bore.html?ref=category:1234874

Can even go with alum D-port heads, if you got an extra $1500 or more to spend on heads. 

Can also go with a stroker assembly in a 389 block, to increase cubic inches. 

https://butlerperformance.com/c-123...-stroker-kits-389-blocks-421-480-cu-in.htmlIf

If it were mine, I'd probably go with a later model 400 or 455 block, 6x-4 heads, a '72 iron intake & an 800 cfm Q-jet. I'd also use the later model timing cover, with 11-bolt water pump, and all later model pulleys, etc, since they are easier to find.

"...wanted to keep it original..."

But, obviously, if you wanna keep it lookin more original, my way would not work.

So, I assume it depends on how original you want it to look, how much power you want, & how much you can spend on it.


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## renorealtors (Apr 7, 2018)

What a help this is. I will get the frame and drive train back to my shop while the body guys work on the shell. I have been advised the stock compression is around 10-1 and premium gas will work. I have also seen Edlebrock makes a package from the short block up to carb that is matched for the GTX 440 and wonder if anything exists for the Pontiac? A lot will be reveled once I get the motor back. I would like to keep the original engine if it is # matching. Are the Pontiac engines # matched to the car as with the trans and rear end?? Thank you John


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## bigD (Jul 21, 2016)

"...Are the Pontiac engines # matched to the car..."

Yes.

If original, I'd keep it for future resale, with car, and build or buy a 400 or larger Pontiac engine, with all later model parts.


"...Edlebrock makes a package from the short block up to carb that is matched for the GTX 440 and wonder if anything exists for the Pontiac?..."

Yes, but I don't recommend the total Edel package. Can get better parts, which will be better suited for your engine, buying separately. And, can save a few bucks also. Very few Pontiac guys recommend an Edelbrock carb. The only E-carb I'd buy is a used or rebuilt Edelbrock Q-jet, which they no longer sell, new.

There are guys here who can give you a detailed list of the parts you'll need to build an engine to fit your needs. It can be built with a 389, 400, 428, or 455 block. Or, for a couple of thousand more, you can go with a really strong aftermarket block. You can go with iron Pontiac or aftermarket alum heads and/or intake manifold. Can go with Q-jet or Holley type carb, or one of several FI systems. Or, you can go with a rebuilt AFB carb, to look more original. There is even the 3 deuce carb option.

There are several good Pontiac engine builders who can sell you the parts to assemble your own engine, or build it for you, in most any stage of completion you want. Prices range from less then $5000, to well over $10k.


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## 1968gto421 (Mar 28, 2014)

bigD said:


> There are several good Pontiac engine builders who can sell you the parts to assemble your own engine, or build it for you, in most any stage of completion you want. Prices range from less then $5000, to well over $10k.


If you wanted an affordable "crate" engine for your car, here is one rebuilder who has a good rep:
Len Williams Auto Machine

And as bigD mentioned there are parts suppliers and rebuilders who can help, notable is Butler Performance :
https://butlerperformance.com/

And for every part you need, be it exterior, interior, engine, cooling, etc., there is Ames one of the oldest Pontiac suppliers:
Ames Performance Engineering, Classic GTO Parts, Firebird Parts, and Full Size Pontiac restoration parts.
Browsing through their print catalog is like a candy store for kids, only here it's for Pontiac people.

Best of luck!


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## renorealtors (Apr 7, 2018)

Great replys! I am googleing how to read the #s to see if they are #s matching. I could easily buy a nice crate short block and then build the rest on my own. How do you up lode pics so I can give you guys updates?? I have started a you tube series " JT'S Customs 65 GTO restoration Part 1" figure it will take 5 or 6 videos to complete the resto. Thanks again for the help.


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## bigD (Jul 21, 2016)

"...I could easily buy a nice crate short block and then build the rest on my own..."


If you post where you live, we can give info on Pontiac engine builders closest to you.

The Len Williams engines, which were mentioned, are the cheapest good quality Pontiac crate engines I'm aware of. 

Len Williams Auto Machine

But, there are good quality higher priced Pontiac short blocks available from many good Pontiac engine builders. 

https://www.facebook.com/PaulKnippensMuscleMotors/

pontiac crate engines

Services

https://butlerperformance.com/c-123...-kits-short-block-kits-ready-to-assemble.html

Kauffman Racing Equipment

Pontiac engine builder

https://www.facebook.com/groups/365435830492976/

https://www.facebook.com/groups/365435830492976/admins/

https://www.facebook.com/pages/Koerner-Racing-Engines/158663244168447

If you live near North Louisiana, my engine guy can build a good short block for you. He's built some 9 sec Pontiac drag engines, as well as 700hp + street & dirt track racing Pontiac engines.


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## the65gto (Oct 9, 2008)

Nice post, great list.


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## renorealtors (Apr 7, 2018)

Hi guys, I have just confirmed the drive train is all original so I now need an engine builder in the Reno Nevada area?? I need a core support and drivers inner fender?? What hop ups would you do for the motor keeping the original look outside??


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## renorealtors (Apr 7, 2018)

Keeping the car stock and original is the thing to do now so I really want to build it so the value is there but will kick some ass at Hot August Nights. Thinking of motor internal mods but will that be a bad move? I just have to keep the car original and I just got a look at the original color( Teal Turquoise) and LOVE it. There was a big area in the door jam to look at once the front clip was removed, all shinny and original and it looks so cool.


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## PontiacJim (Dec 29, 2012)

I think if you do a search using the red "Search" (also says "Custom Search" on my screen) entry at the upper right hand corner that you should find a number of posts on the 389 build to get some ideas of what you might want to do with your build. :thumbsup:


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## renorealtors (Apr 7, 2018)

Got a small bit of the Teal Turquoise from the paint shop and sprayed base coat clear coat on a side cover I had laying around. It looks like a match. Can't wait to put it up against the small area of original paint on the car. Painting the side cover gave me an idea, I will paint a green 71 Honda cb750 I have the same color and tow it around Hot August Nights with the GTO. Won't be this year but for sure 2019.


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## renorealtors (Apr 7, 2018)

*Some pics*

Pics of the build


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## PontiacJim (Dec 29, 2012)

Just remember to take a lot of pics as you disassemble, and bag & tag all items, and do a drawing if you need to because like most of us, by the time you get to assembling, you'll be wondering where this "thing" went and how does it go back together - especially if it is deteriorated and falls apart when pulling it making it no longer identifiable. :thumbsup:


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## cij911 (Oct 25, 2017)

renorealtors said:


> Got a small bit of the Teal Turquoise from the paint shop and sprayed base coat clear coat on a side cover I had laying around. It looks like a match. Can't wait to put it up against the small area of original paint on the car. Painting the side cover gave me an idea, I will paint a green 71 Honda cb750 I have the same color and tow it around Hot August Nights with the GTO. Won't be this year but for sure 2019.


Looks like you have painted before ....wish I had your skills


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## renorealtors (Apr 7, 2018)

Thank you. I do motorcycle restorations and I have a u tube channel " JT'S Customs " with videos of my builds, shop, and small spray booth in the basement. Too bad it is so small or I would paint the car my self. I have hired a guy locally to paint it. Very exciting. Still need someone in Reno to build the motor. I could do it but just can't learn to do everything so I will stick to bikes. A shop locally called Trans Craft is Very Good and Michael will rebuild the 4 speed. if you look at the picture of the trans it looks like the drain plug has never been out? The rear end will go to Bayshore Truck also very good work but the motor is much harder to figure out. I have spent hours reading the posts on the forum and have made many notes. Your help is the best! Thank you.


Coupl more questions. If the picture loaded it shows power windows but they did not come from the factory but look like GM. Could it have been installed at the dealer?

2nd, Is the tach and gauges in the right location? some pics on the net show them in different locations??


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## renorealtors (Apr 7, 2018)

Update on the 65 GTO build. I have a pic of the color, distributor #s , and Head #s Any ideas on getting the right color match in base coat/ clear coat. also if you can pass along your opinion on the distributor and heads. The #s on the head is 77 and it has a strange plate over the rockers??


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## renorealtors (Apr 7, 2018)

New motor option. After bringing the #s matching block to the machine shop " Herbert Performance" in Reno one option they want me to consider is a new IA II Block and store the old block? I have a somewhat big budget for this build and would love to go that direction? Is there a " go to - Proven " Set up for pump gas? There are quite a few displacement choices. It need to run on pump gas and although I will be using it on the street I am no stranger to HP but I'm no Pontiac guru?


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## BearGFR (Aug 25, 2008)

Not a bad move at all. It's a little more challenging (and more expensive), but building a very strong yet stock and original appearing 389 is possible. The things you don't want to change are the things that are visible from the 'outside' and have numbers on them that can be checked. i.e. block, heads, intake, transmission, etc. The things you have free rein over are the things that aren't visible without disassembling the engine: crank, rods, pistons, cam, valves, lifters, etc.... On the "todays unleaded fuel and valve seats question", there are two opinions on it. One says in effect, "don't try it, you'll destroy the heads". The other says, "not so fast - yes, it's possible for that to happen but only if the engine is regularly put under heavy loads for long periods of time, i.e. hauling trailers, making long hill climbs, or LOTS of racing. Otherwise it's not a huge concern." I'm in group #2 (your mileage may vary, void where prohibited by law, etc.) --- so make up your own mind on that one. It's also quite possible to have those original heads machined - have the old valve seats cut out and replaced with inserts that are hardened for unleaded fuel and thus upgraded - at a cost of course - if that's a big concern.

Moving on. The hardest thing about building a 389 is finding pistons, actually "off the shelf and reasonably priced" pistons. And you'll definitely want to replace them in order to lower the compression ratio to a point where it'll be safe to run on lower octane fuel. There's a formula for computing compression ratio and to use it you need some detailed information on the engine: cylinder head combustion chamber volume (measured - don't use factory specs because they are usually off some), head gasket bore size, head gasket compressed thickness, cylinder bore size, piston deck clearance (how far below the top of the cylinder is each piston when it's at the top of its stroke - Pontiacs from the factory are commonly 0.010 to 0.020 "down"), stroke, and how much volume is in the piston valve reliefs and dish (if dished). I have a spreadsheet I built for doing the calculations if all the dimensions are known - I've posted it here a few times over the years. Speaking of compression ratio, that's another area where you'll find several different and passionately held opinions. They range from "never ever go over the 'octane rating' i.e. 9.3:1 for 93 octane fuel, 8.9:1 for 89 octane, etc - period" to "static compression doesn't matter. what matters is this thing called dynamic compression that is a combination of static compression and valve timing, the theory being that the engine can't build cylinder pressure until the intake valve closes, so the later that is the more compression you can run and still be ok." Personally, I'm somewhere in the middle. I don't take a completely rigid view as far as the octane rating but I don't buy into the whole "dynamic compression" hoopla either because of this inconvenient thing called Volumetric Efficiency and how cam timing, air flow velocity, and those pesky Newton's Laws of motion all combine to absolutely start building cylinder pressure even before the intake valve closes as RPM increases. (Long story for another time). I do know this: the consequences of "being wrong" about how much compression you can get away with are significant. It destroys engines. Also the difference in horsepower output between a 9.5:1 engine and a 10.5:1 engine, all else being equal, is less than 10 or 15 HP. For me it's not worth the risk to try to push the limits. Again your mileage may vary....

Back to pistons. They're hard to find for 389's but there are quite a few businesses that would happily build you a set of really nice custom pistons in whatever dimensions you need --- they're just expensive if you have to go that route is all.

If money were no object and I wanted to build a killer yet stock appearing 389, I'd start by stroking it. Change the stroke from the stock 389 3.3750 to 4.250 using a readily available aftermarket crankshaft, and you now have 440 cubic inches. Next I'd send the heads off to a reputable and skilled "head guy" and have him work them over - reshape the ports, clean up the chambers, put in strong 7/16 rocker studs, prep them for whatever springs I'm going to need for the cam I'm going to run, fit the best and largest valves possible. Choosing a cam is compromise. You have to be honest with yourself about how you're really going to be using the car and also what all else can be affected by cam choice --- rear gear, power brake booster (low vacuum), torque converter if it's an automatic car, how strong is the rear axle, etc. A big lumpy cam is lots of fun and you'll get envious looks when you cruise through the local drive in, but you'll be hating it if you have to run a really low gear and can't drive the car on the highway because it's already spinning 3500 rpm at 60 MPH and your brakes are sketchy because your power brakes don't work so well. For cams in general, I personally like rollers over flat tappet cams. Rollers are way more expensive, but you don't have to worry about wiping out a cam lobe because of oiling issues or having to add a bunch of additives to your oil to avoid that. Rollers also let you 'get away' with more duration without also adding as much overlap as you would with a flat tappet cam. Overlap is what kills low RPM torque and also is responsible for that "cool drive in sound" everyone likes so much. It sounds cool, but what's actually happening is the engine at low rpm is so inefficient that it's stumbling all over itself just to keep from stalling.

It's all quite possible, but to quote A.J. Foyt: Speed is just a question of money. How fast do you want to go?

Bear


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## PontiacJim (Dec 29, 2012)

BearGFR said:


> Not a bad move at all. It's a little more challenging (and more expensive), but building a very strong yet stock and original appearing 389 is possible. The things you don't want to change are the things that are visible from the 'outside' and have numbers on them that can be checked. i.e. block, heads, intake, transmission, etc. The things you have free rein over are the things that aren't visible without disassembling the engine: crank, rods, pistons, cam, valves, lifters, etc.... On the "todays unleaded fuel and valve seats question", there are two opinions on it. One says in effect, "don't try it, you'll destroy the heads". The other says, "not so fast - yes, it's possible for that to happen but only if the engine is regularly put under heavy loads for long periods of time, i.e. hauling trailers, making long hill climbs, or LOTS of racing. Otherwise it's not a huge concern." I'm in group #2 (your mileage may vary, void where prohibited by law, etc.) --- so make up your own mind on that one. It's also quite possible to have those original heads machined - have the old valve seats cut out and replaced with inserts that are hardened for unleaded fuel and thus upgraded - at a cost of course - if that's a big concern.
> 
> Moving on. The hardest thing about building a 389 is finding pistons, actually "off the shelf and reasonably priced" pistons. And you'll definitely want to replace them in order to lower the compression ratio to a point where it'll be safe to run on lower octane fuel. There's a formula for computing compression ratio and to use it you need some detailed information on the engine: cylinder head combustion chamber volume (measured - don't use factory specs because they are usually off some), head gasket bore size, head gasket compressed thickness, cylinder bore size, piston deck clearance (how far below the top of the cylinder is each piston when it's at the top of its stroke - Pontiacs from the factory are commonly 0.010 to 0.020 "down"), stroke, and how much volume is in the piston valve reliefs and dish (if dished). I have a spreadsheet I built for doing the calculations if all the dimensions are known - I've posted it here a few times over the years. Speaking of compression ratio, that's another area where you'll find several different and passionately held opinions. They range from "never ever go over the 'octane rating' i.e. 9.3:1 for 93 octane fuel, 8.9:1 for 89 octane, etc - period" to "static compression doesn't matter. what matters is this thing called dynamic compression that is a combination of static compression and valve timing, the theory being that the engine can't build cylinder pressure until the intake valve closes, so the later that is the more compression you can run and still be ok." Personally, I'm somewhere in the middle. I don't take a completely rigid view as far as the octane rating but I don't buy into the whole "dynamic compression" hoopla either because of this inconvenient thing called Volumetric Efficiency and how cam timing, air flow velocity, and those pesky Newton's Laws of motion all combine to absolutely start building cylinder pressure even before the intake valve closes as RPM increases. (Long story for another time). I do know this: the consequences of "being wrong" about how much compression you can get away with are significant. It destroys engines. Also the difference in horsepower output between a 9.5:1 engine and a 10.5:1 engine, all else being equal, is less than 10 or 15 HP. For me it's not worth the risk to try to push the limits. Again your mileage may vary....
> 
> ...


Another good post Bear, but his last post shows a new direction. Might be a time zone thing looking at the times the posts are put up?: 

"New motor option. After bringing the #s matching block to the machine shop " Herbert Performance" in Reno one option *they want me to consider is a new IA II Block and store the old block?* I have a somewhat big budget for this build and would love to go that direction? Is there a " go to - Proven " Set up for pump gas? There are quite a few displacement choices. It need to run on pump gas and although I will be using it on the street I am no stranger to HP but I'm no Pontiac guru?"

:thumbsup:

If you have the big budget, why not just buy an IA II engine complete from one of the many proven Pontiac engine builders and be done with it? Then there is no worry as to matching parts or guessing what to do and how. HP & torque numbers will be known, possibly the engine even broke in, and just insert and run it.

https://butlerperformance.com/i-244...-cu-in-w-iaii-block.html?ref=category:1267471

Kauffman Racing Equipment

engines

http://www.spottsperformance.com/

Buying a block of that type would be a waste with anything less than an all out aim at 575-650 HP. I'd go with the largest cubic inches I could using a forged crank so I could spin the engine around 6,500 RPM's. Big flowing aluminum heads & Roller everything.

Then I would get a custom aftermarket frame that will handle the HP & TQ instead of twisting yours along with the car's body panels, a racing transmission (ditch the Muncie as it will not hold up), and Ford 9" rear end. :thumbsup:


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## BearGFR (Aug 25, 2008)

LOL - I started writing all that before he posted the update about going IA-II. Yeah, if you're going to save the original engine and put in a "fun bullet", you'd be hard pressed to find a better solution for less money than just buying a Butler crate engine outright. Give them a call and talk it over with them. They can help you put together a complete package and also help you with other drive train upgrades that would be advisable for whatever power level you choose.

Bear


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## PontiacJim (Dec 29, 2012)

BearGFR said:


> LOL - I started writing all that before he posted the update about going IA-II. Yeah, if you're going to save the original engine and put in a "fun bullet", you'd be hard pressed to find a better solution for less money than just buying a Butler crate engine outright. Give them a call and talk it over with them. They can help you put together a complete package and also help you with other drive train upgrades that would be advisable for whatever power level you choose.
> 
> Bear


LOL. Don't feel bad or crazy, have done the same thing myself and thought WTF?

PontiacJim


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## renorealtors (Apr 7, 2018)

What great posts!!! What got me re thinking the crate motor idea is the frame twisting? My first intuition was to do what Bear suggested, Stroke the original block. This is more and more what direction I feel I should go. I want to keep the Muncie 4 speed and 10 bolt rear end and putting in the monster motor looks like complete modification of the drive train and some frame work. I am already doing the willwood 4 way disks and the TVS Hotchkis kit with tubular upper and lower a arms with the fox shocks. Frame, trans, and rear end replacement is just out of the question for me right now. 

So far what I am reading is a butler 4.25 stroker kit with dished pistons and fly in the face of " Squelch " or find a piston maker to do a one off in a "D" shape ect. Go with original compression and use additive in the fuel. last but not least work over the heads with hardened seats and stainless valves and some porting? Have you seen anyone use the butler supplied Ross dished piston with good results? 

Romancing the Super Crate Motor is fun but I really will not use that power in cruise lines or stop light to stop light. I just want a great sound and the ability to burn the tires now and then. The stroked motor original block should satisfy these requirements? .

Heads are the trick? I almost get the impression it is not 100% positive the original seats will fail on today's pump gas?? Is this the case, could I just freshen up the heads and run them with just additives?? 

Getting the right cam is a whole other novel so if I can just get the rotating assembly figured out that would be optimal. 

Butler said to go 4.25 kit, 30 over on the bores, 87cc edelbrock heads, "0" deck, and .40 head gasket. I like this idea and wonder what you guys think. This would keep the block date code correct as well as the drive train but I would give up the heads, intake, carb, and distributor. I am good with that and feel the car will retain enough of the original components to be considered date correct.

BIG thank you for your opinions.


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## BearGFR (Aug 25, 2008)

Sounds like a good plan to me so far. The problem with the heads and unleaded fuel is the exhaust seats. One of the functions of lead in the fuel (in addition to octane) was to provide lubrication and cushioning for the exhaust valves,. Without it, what can happen is that the valves 'hammer' the seats and cause them to recede into the head. That's what I was referring to - some folks say that's always a concern, others say "it depends" on how heavily the engine is being loaded on a regular basis. If that worries you, then a competent machine shop can cut out the existing exhaust valve seats and install new ones that are hardened inserts and can take 'whatever happens' with unleaded fuel. The Edelbrock heads already have hardened seats so that's not a problem.

Rear end.... If you build a strong engine, even a 440 stroker out of your 389, unless you 'baby it' (and where's the fun in that?) then that 10-bolt is going to be borderline strong enough. I'd go with one of the ready to run 9-inch's myself and never worry about it. I'm not a fan of the 12-bolt because of the c-clip issue.

If you take Butler's advice and run the 87cc Edelbrock heads, you'll definitely like the results --- but the engine won't be 'stock appearing' any more (if you care). I've seen folks go to the trouble of grinding all the markings off those heads and painting them to try to disguise them, if you want to do that much work, but still one look at those center exhaust ports even absent the Edelbrock logo is going to be a dead giveaway to anyone who knows Pontiacs. You're choice there.

And on the quench ( you called in squelch I think) issue. You're right to be concerned about that. If you do end up needing dished pistons to get compression where you want it, make sure those dishes are D-shaped and not round. That's how you deal with that.

Bear


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## renorealtors (Apr 7, 2018)

Thanks Bear. My plan is to put in the 10 bolt and run it for a while and if need be go to the ford 9" Next is to break down the engine to determine if the bore is stock, then order the 4.25 stroker kit. after I get that far I will start to figure out what cam to run. Thanks again for the time and input.


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