Edit: Dwayne, also found a thread where you tested 1 7/8" vs. 2" dyno headers on a 542 and the 1 7/8" were down 40 hp at 6000 rpm. That's significant and is definitely highlighting one of the compromises of using the available off the shelf TTI headers on this build.
Actually, the dyno headers are 2-2 1/8 x 4……..and the FW headers used in the car are 1-7/8 x 3.5
Peak to peak the power was: 718@6000hp Dyno 678@5900hp FW(-40)
At the top of the pull the power was: 686hp@6800 Dyno 637hp@6800 FW(-49)
The FW headers were big winners down below where the converter stalls……..up 57ft/lb @4000. But peak TQ was slightly higher for the dyno headers. 677@4500 dyno 673@4500 FW
I’ll quantify this statement by stipulating; “on the dyno here”…….. I don’t think it’s going to be slam a dunk that you can make an “easy” 725hp………..with a TF headed 540, on pump gas, with a valvetrain/drag n drive friendly camshaft……..using 1-7/8” headers………especially if they have 3” collectors.
The motor that produced those numbers above was about 11.5cr and used prepped Indy EZ-1’s(about 340cfm), a 440-3 manifold and an 1150 Dominator carb. Doing nothing but swapping the heads for TF270’s may or may not have gotten the power solidly over 700 while retaining the small headers.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
