[RamAir02]

Originally Posted by kwav8r

Gonna chime in on the header question...

The OEM tri-Y exhaust manifolds on these motors are actually very efficient and unless you plan on really increasing the amount of flow through the engine they are more than sufficient. To a lot of people this is heresy, and it’s likely their experiences with older LS or other setups where they were able to achieve decent gains with just improving the exhaust end of whatever they were running.

In the past couple of years I have read more than one article demonstrating that the gains to an otherwise OEM motor in this day and age is somewhere in the neighborhood of ~10-20 horsepower. When you consider the cost of long tube headers, to me, it’s just not worth the expense. Having said that, I did go with a secondary cat delete with an X-pipe setup but, I did that because I wanted a deeper exhaust note. What I also got was more rasp and some drone than I didn’t want and ended up putting a resonator back into the equation- kind of an expensive way to get a deeper note BUT, I got what I wanted. But I digress.

Personally, IF I decide to open the motor up (port blower, heads, O/D pulley, larger bore TB) then it would be shortsighted not to increase the exhaust end of the motor as well. All of these mods work in concert with other mods. While we are able to gain a few ponies here or there with simple bolt-ons, you really don’t need to spend the coin for headers, UNLESS, you want to and then go for it. For the record, I’m not knocking the guys that swear by headers, I’m just not one of them anymore.

My .02

Excellent explanation. Thanks for the detailed information about headers on the ZL1. Makes perfect sense and I'll likely hold off on them until after some other performance mods which will increase the gains seen from opening up the exhaust.