Quote:
Originally Posted by rich-allen
With my heads, cam, roller rockers and intake, I need 1-7/8" headers and SS works doesn't make them.
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Rich,
I wouldn't assume you need 1 7/8 headers. In fact, I'll go stronger than that - 1 7/8 headers may very well lose average power compared to 1 3/4 on your combo. You have to remember that LSx motors have about 1.60 dia exhaust valves, and exhaust ports no bigger than about 1 5/8 at their widest dimension. Going too large on header diameter just loses scavenging efficiency without substantially improving flow, because the exhaust port becomes the primary restriction.
My LS1 AFR/FAST 90/Cam car made an easy 453 RWHP with 1 3/4 headers. LG motorsports has made over 600 RWHP on radically modified LS7s - with 1 3/4 headers. I'd go with headers that are well constructed and fit. And there are really just three choices for "off-the-shelf" - Stainless works, Hooker, and ATS (ATS will shoot me for calling theirs off-the-shelf).
Edit: And I should add, before Tyler jumps in here, that their 4-2-1 design does offer theoretical advantages in creating a broader powerband, and definite physical advantages in ground clearance. They are the headers I plan to use on my '69 LS7 project, and if money is not a major object ... go for it.