That’s amazingly high vacuum in gear for that combo.

My 383, with slightly more cam was about 7-8” in neutral and 4-5” in gear.

I’d probably start by just lowering the idle speed a bit and seeing how it behaved.


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