New emmisions legal carb.

[Ivan D.]

And that'd be why when replacing my Q-jet and stock manifold I opted for a spread-bore Holley and a Offenhauser split-port intake - even with some timing advance issues, 32/33s, 3.08 rear end, and stop and go traffic, I still manage to get around 10mpg, and that's with a double-pumper carb, mind you. Really, on a street vehicle I'd never put a square bore carb, the spread-bore setup is much more suitable for daily driving. Also, here's a little crazy idea - have you considered a Thermo-Quad carb? It ain't a GM one, but will bolt up to yer stock intake, and I've been told that when it comes to street small block V8 engines the Thermo-Quad and the Q-jets are the most versatile carbs, and of the two the T-Quad is the more user friendly one.