# headers vs stock manifolds



## morris66 (Dec 27, 2010)

hey guys in the process of rebuilding the stock pontiac 350,i was wondering would i be better off installing headers or stick with the stock manifolds. i know headers can be a pain,plus not too sure what brands are the best for this application.any info on this would greatly appreciated.sorry this is for a 1970 lemans sport,which is finally in the paint shop yeah!


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## jetstang (Nov 5, 2008)

I put the 3 tubes Headmans on my 70 Lemans Sport. They were a pita. It shifted into reverse fine, went to forward and the rear tube was on the column linkage, so I disconnected it, probably lost my neutral safety switch in the process.. Had to relocate my prop valve also. Then, I put a motor in my 66, kept my manifolds and sold off the headers for it.. Dougs Headers are the best, but pricey. I'm not sure if headers are worth the hassle.


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## Eric Animal (Oct 28, 2007)

:agree If you don't NEED headers, don't use them! Save yourself money and a mountain of bulldoody!


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## Mr. P-Body (Jan 20, 2011)

Headers will just about ALWAYS make more power. If that's your goal here, no other single "bolt on" will make more usable power. 

Avoid the 3-tube jobs. They don't provide the single biggest benefit from headers, isolating the exhaust pusles from each other. It isn't just a matter of "flow".

Headers are not installed for "ease of installation". Anything worthwhile is going to take effort. Relatively speaking, Pontiacs are actually quite "easy" to install headers, at least compared to other engines and cars. 

For the 350, 1 3/4" primary tubes are the largest you want. Hooker "Comp" headers are well-suited to the smaller engine. Buy them uncoated and have a coating shop put a "thermal barrier" on them. The ceramic coating provided is short-lived.

FWIW

Jim


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## ppurfield001 (Jan 21, 2008)

jetstang said:


> I put the 3 tubes Headmans on my 70 Lemans Sport. They were a pita. It shifted into reverse fine, went to forward and the rear tube was on the column linkage, so I disconnected it, probably lost my neutral safety switch in the process.. Had to relocate my prop valve also. Then, I put a motor in my 66, kept my manifolds and sold off the headers for it.. Dougs Headers are the best, but pricey. I'm not sure if headers are worth the hassle.



I agree with Eric -- headers are a PITA. I eventually went with custom-made headers to make 'em work. However, I LOVE the sound and think once they are bolted up correctly they are worth the effort from a horsepower and sound perspective. Good luck.


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## Eric Animal (Oct 28, 2007)

I remain opinionated! However Mr. P-Body IS a professional, so I defer to his knowledge and experiance.......:cheers Eric


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## ALKYGTO (Mar 29, 2010)

Why not some RA exhaust manifolds? They should flow good for your application. If you stay with your stock manifolds you can "port" them to flow a little better and for sure get a mandrel bend coming out of the manifold.


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## BearGFR (Aug 25, 2008)

Mr. P-Body said:


> Headers will just about ALWAYS make more power. If that's your goal here, no other single "bolt on" will make more usable power. ...
> 
> ... Headers are not installed for "ease of installation". Anything worthwhile is going to take effort. Relatively speaking, Pontiacs are actually quite "easy" to install headers, at least compared to other engines and cars.


:agree Headers are more work, harder to install, almost always have clearance issues that require you to do 'extra work', etc. So it comes down to a question of what matters to you most? If it's the most "bang for the buck" then headers are the answer. If you're ok with a compromise and don't mind giving up a little performance, then the reproduction "Ram Air" exhaust manifolds are a good choice.

On the 69 I'm building, I went with a set of Doug Thorley headers that I bought "plain" and had drop-shipped to Jet Hot Coatings in Arizona, where they applied their 'extreme sterling' coating. The headers are built well, have nice thick flanges, all the bolt holes "lined up", and after installation they sealed well and don't leak. I followed their installation procedure and honestly, it wasn't too bad. I can imagine that for someone who didn't follow the procedure and tried to "wing it", it would have been a nightmare. I had two clearance issues I had to address. One was the brake distribution valve that mounts to the inside of the drivers side frame rail. The headers "fit" without moving it, but the tubes would have been less than 1/32" from the valve and I wasn't comfortable with my brake system being that close to that much heat, so I moved the valve to the top of the frame rail. To do that, I had to modify the mounting bracket and make a longer brake line for the section that runs from the valve towards the rear of the car In my case, that was to an adjustable proportioning valve because I'm also using aftermarket disc brakes. On a 'factory" set up that's a one-piece line all the way to rear crossmember, so it'd probably be easier to instead to get a union fitting and instead add a short piece of brake line onto the front of the long line in order to be able to "reach" the valve in the new location. The other clearance problem was the rear bolt on the lower control arm, passenger side. It rubs a header tube there. It's easy to back off the nut a little bit then whack the bolt with a hammer to dimple that tube just a tiny bit for more clearance. 

TIP: *BEFORE* you install the headers, make sure you check the rear bolts on both lower control arms to ensure that the bolts are inserted from the rear with the nuts on the "front" side of the car (so that the bolt heads are next to the header tubes). Otherwise, the ends of the bolts are probably going to rub holes in the headers. 

Bear


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## morris66 (Dec 27, 2010)

thanks for all the feed back it is very helpful to me. where can you get the r/a manifolds.it seems to me pontiac parts are a little harder to come by this is my first pontiac project but i think this forum is great,with alot of experience from eveyone.thanks again Darin


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## jetstang (Nov 5, 2008)

I like headers on all applications, going against my previous post, but for Chevy's they offer headers for auto and manual trans, and vehicle specific. Pontiacs are pretty generic, they fit everything, but nothing really good, at least the ones I got.


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## Mr. P-Body (Jan 20, 2011)

Our experience with installing headers doesn't "match" many here. But again, following installation instructions makes the whole job a LOT "easier" (a relative term). Seldom are things "in life" that are worthwhile, easy.

You can buy the Ram Air manifolds from Ames Performance or Performance Years. Pontiac "parts" are no more difficult to find than any other "mainstream" brand. However, looking for them IN the 'main stream" will lead to disappointment, CHevy and Ford people don't even aknowledge Pontiacs exist... Ames and PY, Butler Performance, PPR, all good places to get Pontiac-specific stuff.  Engine parts are readily avaible through "normal" parts sources. No NEED for a "specialty" house for pistons, rods, cams, etc.

Jim


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## Stickyfingersfrank (Feb 16, 2011)

*headers vs stock*

i replaced my stock headers with manifoldson my 73 lemans 350 because the thread went out,
i bought the summit racing headers.

bolt on they say....

That was a big job but they did fit without any adjustments,
even though i had to raise my engine to mount them.

The performance went up a little and it just runs smoother and makes a better sound so i never regretted it.:lol:


Frank


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