Stumble off idle -

[blykins]

A 750 would also work for this size engine, although IMO it would be down on horsepower. If you were to use a carb with basically infinite tuning, you could tune the transition a lot easier. The higher end Holley and QFT carbs have adjustable IAB's, HSAB's, IFR's, PVCR's, etc.

However, on 427's and up, I generally use 850's.