well i still prefer mine seen here, but im very lucky to have them.

http://community.webshots.com/photo/...7877pyuyFbJmlW

i imagine that all of the above perform within 5hp of the next. choose which is best for you based on budget/look/brand loyalty/etc.

i also dont think that cam only cars or bolt on cars is even close to being the appropriate way to measure a headers performance... but like i said it depends on the application.. bigger does not directly = better with any engine.

 

BTW, have you guys noticed that other reputable cars use the twisty headers. Ever see the new BMW M3 headers? You'd of thought they came right from SLP!! Guess those German engineers don't know what they're doing <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" />

 

My SLP LT with no cats got me 25 hp 23 ft/lbs. This was a before and after install dyno run at MTI's dyno. There was no other mods done during this run, and no tuning. I was very happy with its outcome. Install was a bitch, but it finally went in.

 

Whisper Headers ROCK! <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

Closing this.. If the original poster has anything TECH related. Start another thread.

 

Grotyohanns are the best hands down. Alot more than just pipe straightness dictates performance of a header design.

 

Don't choose a header on how straight they are.

Exhaust Basics:

There are two MAJOR things that are going to contribute to how much HP your headers are going to get you:

How well they flow: There are a lot of things that contribute to how well your headers are going to flow on your car. Yes, the shape of the header is going to be one of these, and giving your gasses a straight shot verses rather than all over the place is going to allow for more predictable/better gas flow. This should not be the criteria to choose a header though. There are too many factors that contribute to good flow to just say "Straight headers flow better". For example, a 2.5" straight as an arrow header pipe will flow like crap against a 1 5/8" super curvy header pipe for a 350 cfm engine, because the the 2.5" pipe is just to big to maintain proper gas velocity in the header.

Pulsation Managment: I don't know the proper term so 'pulsation managment' will have to do. Good pulsation management will make or break whether or not you have a good header.
As your valves open and close pressure waves are sent through the exhaust system. These pressure waves are mearly a contraction and extraction of the gasses in the exhaust system. As the pressure wave travels down the header tube, it will eventually come into contact with the collector. At the collector, the gases are converging, and moving at a slower velocity. For the pressure wave, hitting slower gasses is like hitting a wall. Some of the pressure front will travel further down the exhaust, while some of it will be reflected back up the header pipe. The trick of pulsation managment is to have the pressure wave develope a low pressure just outside the cylinder just before the exhaust valve closes. What this will do is pull more exhaust gasses out of the cylinder and actually generate a slight vacuum in the cylinder so that more fresh air may be pulled in during the intake stroke. So you can see how important this is. Bad pulsation management can actually cause the reverse to happen and hinder HP.

If you stand two very good flowing headers side by side, the one with the best exhaust pulsation management will absolutely crush the competition. No matter how straight the other one is.