years ago, i had 235/273 dart drag car, I had 1 5/8 headers on it, i swapped to 1 3/4 headers at the track, car went 4 tenths faster,. no other changes. just food for thought. not to beat a dead horse, lol
I'm thinking your combo is on the larger end of the spectrum. Must been something that it REALLY likes about the bigger headers, but I think for the vast majority people aren't going to see that big of a gain from a header swap.
On my one car (mild 440) I went from 2" hooker fenderwell to 2" TTI headers with very minimal difference. Now in that process I did remove the inner fenderwells and ran a bar from the cage to the front of the frame to tie the shock brace to, so it wasn't apples to apples. Last year I had 1 3/4" TTI on the car (2" were just to big of a pain to work in) but this winter I put my 2" hookers back on. Curious to see if I pick up any or not as that is the only change I have made.
