I know this has been beat to death...

I ordered my headers yesterday from SLP. I ordered them through a local performance shop which is hooking me up with a good deal for the installation and some other exhaust work.

I have a 350 and was originally intent on buying the 3/4s but the guy talked me into the 5/8s. I don't plan on going too much over 400 hp by the time I'm done with mods. There's no point in really having the 3/4s if I'm not gonna need it right?

So what do you guys think? I'd be able to get away with the 5/8s with a new intake plus new heads and a cam?

 

If you are planning on staying around 400HP then I think the 1 5/8 should work just fine. From everything I have read 1 5/8 headers start to be a restriction around 450HP. Chevy High Performance magazine just did a test on a 450HP 383 and it made more overall power with 1 5/8 headers than 1 3/4 headers.

 

https://www.thirdgen.org/techbb2/sho...hreadid=116695

Read the whole thing...new info at the bottom...


I would say yes, 1 5/8" will be ok...and the other big thing is better clearance for the spark plugs....

HTH,