dart headers
I wish I had the time and resources to do a back-to-back between regular 1 5/8" headers and TTI 1 5/8"-1 3/4" stepped. But aside from the dyno test link, I did a lot of research on what most fast Mopar small block Stockers were running for headers, as well as some Chevy stuff. I don't recall any that didn't step up to at least 1 3/4" even though some actually started at 1 1/2"! 1 3/4" straight was pretty popular. That's what I based my decision on and someone else will have to do a back-to-back comparison to convince me that a 1 5/8" header wouldn't be a choke-point for similar or wilder combinations.
Weren't there any engine shootouts that small block Mopars were built up?
May have been in the 500hp range though. If less HP, header choices would have been interesting.