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Old 11-17-2003, 04:55 PM
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pontiac stock exhausts the Bomb or Poop?

some pretty smart cookies at the poncho site think there isnt much improvement on stock poncho parts. for the intakes this is true. they are pretty damned good. a performer doesnt improve much on them. there are also some DAMN good stock exhausts that almost look like headers. if i had them i would not look for headers. but mine look like the ususal crappy chevy ones: like an E laying on it's back. i cant believe i wouldnt feel hellacious improvement from replacing them, but there are a few who are telling me to leave them on after i put in a mild cam ( a summit 2800) and an aluminum intake. anybody know for sure if headers are worth the effort? a bud of mine just put thorleys, performer and a 4bbl on his 2bbl 326 (like mine) and said he was surprised how little it did for his boat.

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Old 11-17-2003, 05:36 PM
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The restricting factor here is the cylinder heads... The small valves just don't lend themselves to any good breathing and increasing the flow on either side doesn't help.
I know for a fact that a good set of heads will do more for power then any intake or exhaust will do up to that point and, until you get the motor to breath, your just wasting your time and money.
Mark
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Old 11-17-2003, 07:58 PM
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Pontiac engines have really restrictive exhaust ports. Believe me, as I have ported several sets of Pontiac heads, and they have an unbelievably bad exhaust port. If you will notice, most good Pontiac cams have considerably longer duration on the exhaust side. The intake port is a pretty good piece, and lends itself quite nicely to making a 250+ CFM of airflow, but getting the exhaust to flow 80 percent of intake is not an easy task. So, anything to improve breathing on the exhaust side of a Poncho is a real benefit, like good, four tube headers. I'll send some pics of a set of 6x-4s I'm doing right now just to show how rough the exhaust ports are from the factory.
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Old 11-17-2003, 08:13 PM
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nairb is exactly right! i did my set of 4's and the stock exaust ports were crap. but if done right they make real for a real good set of performance heads.
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Old 11-17-2003, 09:43 PM
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The drawback to Pontiac-header configuration is either you have to run them open to actually be able to use the scavenging effect headers offer, or not run them at all. The way that the Pontiac exhaust ports are canted down cause a slight enough "kink" in headers to not be able to maximize scavenging as much as a typical chevy head would with full pipes. I opted to keep my stock manifolds on my street car until I could find a set of long branch manifolds, what you refered to as what "almost look like headers". These manifolds do improve flow over stock manifolds, and as your friends tells you, headers aren't gonna give you much on a full exhaust system.
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Old 11-18-2003, 10:03 AM
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that's it, you guys just all made my buddy list.
that's really good dope. the logic behind it. you just saved me a ton. except for buying those long branches, which cost as much as headers!
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Old 11-18-2003, 12:43 PM
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Never mind - just noticed that you have the 326, and the log exhaust manifold could be okay with that displacement. When you get to the larger engines, the same manifold that works okay for the 326 becomes too restrictive for a 462.

Last edited by lust4speed; 11-18-2003 at 12:49 PM.
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Old 11-18-2003, 01:32 PM
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http://www.ramairrestoration.com/generaluse/

Quote:
from Ram Air Restorations site:

Think factory style headers are still too restrictive or power limiting?

Here's one example of how efficient they are in turning your car into a Torque monster and by delivering the same power improvement that a tube header does for any street/strip Poncho (without the tube header "blues"......clearance probs, ticky-noisy, burning gaskets, rust thru, crunched tubes, unable to get to all needed bolts, floor heat, etc.)

A recent dyno test of a 455 + .030 with single 4bbl, Crower cam and ported heads using our 2.5" collector Ram Air series headers & 30" of 2.5" pipe produced 517.2hp @ 5600 rpm, 607.0 ft lbs @ 3800 rpm.

Granted, there's nothing like headers on a stout motor but these Ram air manifolds flow pretty well.

Bullheimer, if you have eventual plans to put something more wild in your car, buy what you need now so you're not spending money on things twice. If you plan on keeping the 326 for a while then stick with the logs. Just my opinion...
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Old 11-18-2003, 04:47 PM
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well i dont have the long branches, and those are the manifolds you are talking about above. if you look at the price of those suckers on that site, over, well over $300, you know that ceramic coated headers from jet hot are the same price. so why bother. and if you look at them, for those who havent seen them, they look like headers anyway. they definitely are the baddest design that gm ever came up with. and your right about my little motor not really needing much, esp with what is said about the lousy heads. btw i love that avatar two back
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