The biggest changes I’ve seen usually revolve around some component that’s either not working right, or isn’t a good match for the rest of the combo.

The biggest differences I’ve seen have come from these items....... but not at all consistently.
For each instance where I saw a big change....... there would be dozens where it did nothing.

- cams
- carbs
- intake manifolds
- swapping to a tunnel ram
- vacuum pumps
- headers

68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads