I'm glad this was brought back up. It's interesting because the combo I'm running now is VERY similar. Same carb, same TTI headers and same heads - unported with 1.92/1.625 valves. Main differences are forged flattops with around 10.5-1, Holley Strip Dominator, 1" 4-hole tapered spacer, "Stocker" (lots of duration) cam with .474" lift and 1.5 Harland Sharp rockers. I never had it on the dyno, but I've gone 11.22 @ 116+ weighing 3,540+ lbs and it can be "tuned-up" to go 11.00's. Hoping for a high 10 under the right conditions, but only if I really need to.
There was a Mopar Muscle or Hot Rod dyno comparison between TTI and Hooker smaller and bigger headers. TTI showed an advantage on the mild 360 and would probably be more on a wilder one. I just don't recall the #'s & don't have a link.
The initial TTI 1 5/8" size is not a restriction in most cases and the header seems to flow like a 1 3/4". In fact, some "Stock" class small block race cars start off as small as 1 1/2" and take 1 or 2 steps. Several Mopar Stockers use the TTI's.