I ran a stock ish 440 (915 heads, no porting), MP 272 - 0.455" lift cam with manifolds and a factory intake. Best running carb was an 800 Holley DP.

Then we put that same carb/intake on a friend's stock ish 440 GTX, and it picked a a couple tenths and mph too over a 3310 Holley vac. carb.