I need to talk to someone about it that knows more than me that's why I'm asking.
Unless someone has tested a motor combo that's very close to yours with both sizes of headers you're talking about, and they're willing to share that info, you might have to test if for yourself to find out exactly what the answer is....... On your motor.
100+ hp seems like a stretch for a header swap to me....... But that's what the dyno is for. To provide answers to those questions.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
