Joel Adams
C3VR Lifetime Member #56
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
A vacuum secondary BG is a great carb. A 750 sounds like a good size for your 383...call them directly with your specs and they will tell you the best application.
Just curious, what makes you sure the HG won't help? It should lower the compression at least a few tenths. I can't run race fuel, it's a DD and I'm not that rich haha. But when you say "it's the tune" what do you mean? I tried 2 sizes higher on the jets and a size smaller on the rods. The dist has the heaviest springs possible, and it does it even with the vac advance unplugged. I'm not sure what part of the tune could fix it?