# Cam and heads for 71' lemans 350



## SPCMarty (Jul 29, 2011)

I'll just apologize ahead of time for my lack of knowledge. I don't want to swap out the engine with a 400 or 455. Hoping I can get good suggestions for an aftermarket or OEM head and camshaft pairing to open up my lemans' engine. It's got a edelbrock performer intake and I'm looking for a 650cfm carb to replace the 750 edelbrock it has now.


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## ALKYGTO (Mar 29, 2010)

IMO you're wasting your time modding that 350. Good dual exhaust, maybe some gears, good tuneup, save $$$ for 455 swap. They are still out there and you can swap in a weekend.










Pontiac 350 is not a Chevy 350 and never will be; you can't turn a sow's ear into a silk purse.


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## Instg8ter (Sep 28, 2010)

Eddy heads will set you back a few grand, best (most economical and easiest) way to pep it up would be 650 carb, 1:65 rockers (a bit more lift without replacing the cam) and dual 2" exhaust. you probably also have a 2:XX rear end gear, change that to a mid 3:XX and it will get up and go a little better but wind up a little more on the freeway.


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## BearGFR (Aug 25, 2008)

Also, just in case you don't already know this --- you do realize that putting in either a Pontiac 400 or Pontiac 455 would literally be "plug and play", right? All real Pontiac engines are identical in physical size, shape, bolt patterns, etc.

Walk up to a line of Pontiac engines sitting on a shop floor, 326, 350, 389, 400, 421, 428, 455 ---- the only way to tell one from the other is to start reading and interpreting the various codes and stampings on them.

Bear


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## SPCMarty (Jul 29, 2011)

I thought the 350 HO was quite the engine? but y'all say it's pretty futile to build it up, what makes the Pontiac 350 so much worse than the Chevy 350?
I did know the 350 and 400 were the same dimensionally


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## BearGFR (Aug 25, 2008)

SPCMarty said:


> I thought the 350 HO was quite the engine? but y'all say it's pretty futile to build it up, what makes the Pontiac 350 so much worse than the Chevy 350?


Hold on there cowboy....  It's not "worse", just different. Actually, the core of the issue is the fact that there a eleventy-gazillion bowtie 350's (and other varieties of mouse motors) out there. It was in production a very long time, a lot of them were sold, they were cheap to build, cheap to buy, cheap to work on, etc. (Did I mention they were "cheap"? ) One of the results of that situation is that there are TON's of aftermarket parts out there for them and also TON"s of research/knowledge/experience on how to build them.
They're easy. For me that also makes them BOOOOORRRRINGGGGG! (but that's just me).

The Pontiac 350 wasn't produced or sold in anywhere near the same numbers, the dimensions (bore and stroke) are different, the heads are different, etc. so that makes their personalities different. Things that work on one o' them (cheap ) orange motors don't necessarily work the same on a Pontiac. Couple that with the fact that the availability of 'go fast' parts available for them is a mere fraction of what's out there for "the others", and you can begin to understand why you don't see nearly as many fast Poncho 350's. It's not that they "can't", it's just more expensive because of lower demand for parts and also in order to build one you have to actually "think". 



> I did know the 350 and 400 were the same dimensionally


Oh yeah... so if you're interested in what it sounds like you're interested in (going fast on the cheap) then you, sir, are in the cat bird seat as it were. All you have to do is be patient, find yourself a nice decent running stock Pontiac 455 in good condition that already has a 4bbl carb on it (like from Grandma's station wagon or uncle Joe's Bonneville), unbolt your 350, bolt in the 455, and then hang on to your butt.... 

It really is that easy.

Be too abusive and the big torque from the 455 is probably going to overpower your existing drive train (rear end and transmission) and start breaking things, but the beauty of it is that you can work on the car a little at a time, upgrading parts of it as you go, having a blast surprising and embarrassing the bowtie brigade the whole time. You'll even be able to raise the hood and say, "yeah, it's just the original 350" and get away with it most of the time 

Now... don't that sound like fun??? arty:


Bear


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## SPCMarty (Jul 29, 2011)

A new transmission is a higher priority anyway and higher rear end ratio. Likely a tremec 5 or 6 speed conversion. 
I do have some money to mess with, I just don't have my own garage to house and work on a 400-455 outside the car. All the eBay ones are pick up only. A 400 is more likely to be found but I think the 1971+ 400s were hindered by emissions laws. 
What about a Stroker kit for the 350? Any opinions on those.


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## BearGFR (Aug 25, 2008)

SPCMarty said:


> A new transmission is a higher priority anyway and higher rear end ratio. Likely a tremec 5 or 6 speed conversion.
> I do have some money to mess with, I just don't have my own garage to house and work on a 400-455 outside the car. All the eBay ones are pick up only. A 400 is more likely to be found but I think the 1971+ 400s were hindered by emissions laws.
> What about a Stroker kit for the 350? Any opinions on those.


Sure, you could do that. Two things are going to be problematic - really - two things... the heads. If those are 350 heads they may have eensy tiny little combustion chambers, and once you start pumping up the displacement you're very quickly going to get to the point where compression ratio will be -way- too high to live (for long) on pump gas. Building a stroker isn't cheap. There's more involved than just purchasing the "kit". You've got machine work, and also the cam and valve train, heads, exhaust, etc. have to be optimized to take advantage of the new inches - otherwise it's a waste.

Point is, you've got lots and lots of options - more than one way to skin this cat as Mr. PBody says - if you want "go fast and have fun at minimum cost", then that's the direction I was suggesting - find a reasonably healthy 455 and you're there with minimum cost and maybe a weekend's worth of work. That's not the only way to get there, though.

Bear


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## Josh.AZ.GTO (Jul 11, 2009)

ALKYGTO said:


> IMO you're wasting your time modding that 350. Good dual exhaust, maybe some gears, good tuneup, save $$$ for 455 swap. They are still out there and you can swap in a weekend.


:agree 
If you got a 350 already running pretty good, I'd add some headers and a 2.5" to 3" performance exhaust. I'd clean it up make sure there are no leaks then paint it and touch it up with a little bit of chrome accents.

For the money spent in buying a 400/455 to build up; your $ spent to HP ratio can be maximized. Run your 350 till you can get one built then keep your 350 in case anything happens to your 400/455. 

I have always been intrigued in doing a stroked Pontiac 350. I may attempt it someday, of course after my GTO is done. I would love to do a 70-73 Firebird sleeper with a Pontiac 350 stroked.


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## jetstang (Nov 5, 2008)

I put the 350 back into my Lemans, replacing the mid year 400 low comp motor with good heads, and it lost HP, unless it's a carb issue. I understand what everyone is saying, a good 455 is 500 ft lbs of torque and a tire shredder with a small cam and no compression-incredible. 350 is still powerfull and has plenty of potential to get 400 HP/400 ft lbs of torque at a cost, and can easilly smoke a Chevy. It will take some mods to make the 350 fast, while the 455 is a cheap base but will provide far superior results at less cost.


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## SPCMarty (Jul 29, 2011)

Instg8ter said:


> Eddy heads will set you back a few grand, best (most economical and easiest) way to pep it up would be 650 carb, 1:65 rockers (a bit more lift without replacing the cam) and dual 2" exhaust. you probably also have a 2:XX rear end gear, change that to a mid 3:XX and it will get up and go a little better but wind up a little more on the freeway.


Where would I find these different rockers?

I suppose y'all are right. Headers and dual exhaust are on the list. The odds of finding a 455 seem bleak, and I had an opportunity to get a 400 but it was out of a 75 grand am/prix, which by my understanding were underpowered. 
Finding a positraction conversion and higher ratio, any ideas there?


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## SPCMarty (Jul 29, 2011)

Could I go any higher than 1.65 rockers? I'm assuming id be replacing both intake and the exhaust rockers?


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## Josh.AZ.GTO (Jul 11, 2009)

SPCMarty said:


> Where would I find these different rockers?
> 
> I suppose y'all are right. Headers and dual exhaust are on the list. The odds of finding a 455 seem bleak, and I had an opportunity to get a 400 but it was out of a 75 grand am/prix, which by my understanding were underpowered.
> Finding a positraction conversion and higher ratio, any ideas there?


Try posting a wanted add on craigslist, that is what I did. I got a few people who contacted me who didnt' have anything for sale but when they saw someone was looking for one they did call. I waited almost 5 months before finding a 455 (71 455 325hp). I bought mine off a guy who had the 455 stored for 15 years in his garage. Got it for under $1k, complete carb to pan (with a guarantee to work) and with an extra pair of heads (6x-8). 

If you can be patient I'm sure something will turn up. I'd try posting some wanted adds and see what you hear.


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## Instg8ter (Sep 28, 2010)

1:65 roller rockers are available from Harland Sharp, Comp cams, Scorpion and others, you will want to male sure your heads have screw in studs. The headers intake, all accesories and possibly carb will all swap over to a 400/455 when you find one so you can look for a short block deals are out there, i just took apart a 72' 400 (see budget 400 thread for pics) i picked up for 450.00 and it looks like i could put it back together and run it as is, picked up a 455 short block running in a 72' Trans Am for 1000.00 over the summer because the guy did not like the big cam and was having a numbers correct one built. Just have to watch craigslist in your area, and be ready to go look and hear run if possible then deal on it if it sounds good.


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## SPCMarty (Jul 29, 2011)

So if the rocker studs are push-in I'll have to somehow remove them? Then tap the hole I assume. 
Perhaps I'll put out a want ad once I can afford an engine.


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## SPCMarty (Jul 29, 2011)

Found a 1976 400 engine locally, any opinions on them?


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## Instg8ter (Sep 28, 2010)

look for a pre 75' block as they are stronger in the main webs than the 75+ blocks, where are you located i will keep an eye out...


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## SPCMarty (Jul 29, 2011)

I am up in Duluth MN. Pre 75' and immediate work that should be done to a 400 or 455 before installing? 
Looking out for a Muncie 4 speed or drop the funds for a 6spd tremec.


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## Instg8ter (Sep 28, 2010)

Pontiac 400 engine

This is the last casting that was thicker web.....if you can find one in a car and running to verify it does not leak from the main, or smoke and check the compression to be good you could clean it up, drop it in and go, if not able to hear it run its a crapshoot and I would want to tear it down and verify everything before spending the time putting it in to find out it won't run right. Pontiac blocks are like land these days...."they ain't making any more", 455's used to be a dime a dozen in all the station wagons that were produced in the early 70's, now your lucky to find a rebuildable short block for under a grand.


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## SPCMarty (Jul 29, 2011)

Found nearby 72' 455 in a Catalina. The guy I bought the lemans from said it had somekind of knock. 

Rather than open a new thread. 
Anyone know how I'm supposed to use the #8015 throttle bracket?
And I can't seem to find the carburator gasket to performer 
manifold to


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## BearGFR (Aug 25, 2008)

SPCMarty said:


> Found nearby 72' 455 in a Catalina. The guy I bought the lemans from said it had somekind of knock.


 Which is knocking... the 455 or your Lemans?



> Rather than open a new thread.
> Anyone know how I'm supposed to use the #8015 throttle bracket?
> And I can't seem to find the carburator gasket to performer
> manifold to


Sorry, not familiar with the bracket just from the number - can you post a photo of it? Also of the manifold and carb...

Bear


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## bhotz (Dec 17, 2011)

*pontiac 350*

i wanted to add some thoughts on the 350 vs 455. i have a professionally built 350 that i bought used for a great deal. I dropped it in my 71 trans am clone. I bought the complete motor for a steal, running 3.23 gears and 2500 stall with th350. has demon carb and 280 cam, harland rocker 1.65, no. 16 heads. i just ran it today against my 71 lemans stock 455 (1970 motor) with new 700r4 trans with shift kit and 3.55 gears. My uncle drove the lemans. We went toe to toe from 0-70 mph and the trans am with the 350 easily walked away from the lemans. The ta revs up to 6k with tons of hp and torque - very balanced. The 455 has brute low end but not much left once you get past 4k on the tach. I have to admit I was a little surprised by the results, a 3.55 rear with 700r4 trans is like having a 4.11 rear.

i know there is no replacement for displacement and pontiac builds can be a little expensive but sometimes its worthwhile to see whats out there. A nicely built 455 can put out some major horses sure but the built 350 motor sings and sounds awesome and i picked it up it for less than a good pair of aluminum heads. I'm very happy I decided to run it in the ta. You can check out the t/a at shutterfly below to see how well a built pontiac 350 moves and sounds. The 350 block is from a 69 firebird.

http://71transamrestomod.shutterfly.com/

the password is 71ta


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## BearGFR (Aug 25, 2008)

Man, that's one nice looking (and nice sounding) TA.

Bear


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## bhotz (Dec 17, 2011)

Thanks, the t/a was a 13 month project, it's a blast to drive. I'll add some pictures of the lemans next week, it's no slouch either but the 350 sounds better than the 455.

I added the pictures of the 455 Lemans next to the Trans Am from last week. A couple videos of the Lemans running. For anyone considering a 350 build, this should be a good link to check out. 

http://71transamrestomod.shutterfly.com/

the password is 71ta


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## SPCMarty (Jul 29, 2011)

I can't seem to find the bracket but here is something
http://www.ebay.com/itm/370563693018?redirect=mobile#ht_2008wt_804

I was talking about the 455, but it's gone now anyhow. 
Got an offer for a 8.5 10bolt rear end with 3.42 ratio. Non-posi though which isn't a big deal if a can find a conversion kit.


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## bhotz (Dec 17, 2011)

I updated the link with new photos and videos of the 455 Lemans together with Trans Am Clone with the built Poncho 350. The Lemans and T/A went head to head last week and provided me with a good performance comparison of the two engines. That being said, if I didn't find such an incredibly well built 350 that was ready to drop in, I wouldn't have given much thought to building a 350 over a 400 or 455 block. Both cars sound great and offer plenty of street performance regardless of the block size.

http://71transamrestomod.shutterfly.com/

the password is 71ta


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## SPCMarty (Jul 29, 2011)

Those are both fine cars, and makes me want to build the 350 some. 
So let's be hypothetical and give some ideas on good aftermarket parts, heads, cams, ect. I can afford a fair amount of pieces.


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## ALKYGTO (Mar 29, 2010)

I would'nt add anything that you could'nt utilize on the 455 later or you'll just be spending your money twice. A 455 done right will also increase the value and desirablilty of your car immessly. What a cool sleeper in that tan color.

If it's cheap thrills your after; here ya go...........


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## SPCMarty (Jul 29, 2011)

Not a fan of N2O actually. Nice picture though.


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## russosborne (Dec 6, 2010)

Surprised (well,not really, the 350 gets almost no respect) that no one has mentioned Rocky Rotello's book. He has a couple of 350 builds in it, as well as lots for the other sizes. 

What most are saying is that you will spend the same amount of money (or more) on doing the same stuff to a 350 as a 400 or 455 will cost. I am wanting to go with a stroked 400 for my lemans, but most likely will have to keep the 350 in it for now. But really for a street only car a 350 is plenty, unless you just have to have the bigger size. 

Rear end gears could be the best bang for your buck. An overdrive trans with 3:55 or 3:89 gears would really wake things up but still give you good gas mileage on the highway. 

And you want to make sure to get an 8.5 from an olds or buick if you go that route. 

I actually broke the gears in my old GTO with a 350 engine (the original was shot when I bought the car)and a Muncie four speed. But I wasn't being easy on it either. 

Russ


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## SPCMarty (Jul 29, 2011)

Well I'm at least putting some headers on the 350. 
Though I'm having to remove the starter, oil filter, and think I may need to lift the engine. Is this normal? I got the driver side one mounted but I can't work the passenger one in yet.


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## BearGFR (Aug 25, 2008)

Yep. In fact, it's very unusual to be able to get even one side on without having to lift the engine.


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## SPCMarty (Jul 29, 2011)

Well it took a bit of work to get the driver side in. Looks like I'll need to reroute the starter wires too. 
Is lifting the engine as simple as just the two cross bolts to the mounts?


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## BearGFR (Aug 25, 2008)

Yeah, you can probably just take 1 side loose and tilt it.

Bear

Sent from my Nexus One using AutoGuide.Com Free


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## SPCMarty (Jul 29, 2011)

How about a 455 oldsmobile engine?

olds 455 motor -

http://duluth.craigslist.org/pts/2751224843.html

The seller did request that I not put a Chevy engine in.


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## Rukee (Feb 8, 2007)

SPCMarty said:


> How about a 455 oldsmobile engine?
> 
> olds 455 motor -
> 
> ...


It would bolt to the tranny, but I think everything else will need to be reworked, like the starter wires, fuel lines, exhaust, etc.


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## ALKYGTO (Mar 29, 2010)

SPCMarty said:


> How about a 455 oldsmobile engine?
> 
> olds 455 motor -
> 
> ...


 :confused What, he did'nt want you to make it fast? :rofl:

Put a Cadillac 500 in it. Definitely not the Olds, sorry, they're slugs. :lol:


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## SPCMarty (Jul 29, 2011)

I find something eventually. 
These headers are becoming a nightmare. Had to take the oil filter mount off now too even with the engine lifted and the final bolt to the header won't bite.


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## Rukee (Feb 8, 2007)

ALKYGTO said:


> :confused What, he did'nt want you to make it fast? :rofl:
> 
> Put a Cadillac 500 in it. Definitely not the Olds, sorry, they're slugs. :lol:


 Those cadi 501 engines had a ton of top end torque, but wholey crap were they heavy and big!!


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## SPCMarty (Jul 29, 2011)

I'd like to stick to Pontiac engines anyhow. 
Y'all foresee any complications with drilling the bolt hole larger to compensate for the offset


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## Rukee (Feb 8, 2007)

No, but once you do, they'll be unreturnable, so you better be able to make them work.


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## SPCMarty (Jul 29, 2011)

Can't be returned anyway


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## RustWrangler (Sep 15, 2011)

If you were still looking for a 455 I called this guy about the 389, he said he also has a 455 sitting in a Bonneville (I think? not sure) but he wants to sell the 455 too, I don't know what he wants for it but all it takes is to ask  

pontiac 389

Good Luck!


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## NorwalkNugget (Aug 5, 2011)

Dude I respect you on this. I have a 71 350 as well. Don't believe the hype on them being slow. They're not "slow" but they aren't "speed demons" Forget the HP numbers, it's about the torque and usable torque within RPM range.

Make sure the car breathes right... headers, exhaust.
Make sure you have a strong carb 650+
Clean air filter
Good tranny
No leaks


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## BearGFR (Aug 25, 2008)

:agree Making power is all about air flow. And remember, horsepower is calculated from torque at rpm - torque is directly measured.

Indy car engines are only 3.0 liters (183 cubic inches) but they make around 650 horsepower. How is this possible? Well, they make that 650 horsepower at a rev-limited 10,300 rpm. Do the math. HP = (torque * rpm) / 5252 Work that backwards and you find out that making 650 HP at 10,300 rpm only requires 331 lb.ft. of torque (also at 10,300 rpm) To accomplish that those engines are _designed_ with internals that can live at that rpm (for 500 miles at least) and have heads, intake, valve train, exhaust components that are optimized to place the engine at peak volumetric efficiency when it's at that rpm. The darn things probably won't even stay running at less than 3000 rpm, much less idle.

All engines make exactly the same torque and horsepower numbers at 5252 rpm. 

The motor in the Beast makes _60% more torque _than an Indy car motor -- cool 

Bear


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