Your hestitation could be as simple as an accelerator pump adjustent. Holleys will load up at idle if not tuned properly causing a hesitation. Set your initial timing at 10-12 and set the carb mixtures with a vacume gage.

750 is ok on a boat, a lil big for street. 750 qjets have small primaries and big secondaries, so they are no comparison to holleys-afbs.

I did back to back testing of a 600 and 750 marine edelbrock carb on my 375ish horse 350. The were virtually the same performance. The 600 was best jetted out of the box. The 750 was a little lean just off idle and I went one step lean on the secondarys. the 750 was maybe a mph faster on the top end.

the q-jet and edelbrock are air valve secondary, demand controls air flow depending on carb setup/tune. the air flow calc's can be high or low depending on intake(dual or single plane) would go thru engine/carb and verify tune/setup. I have learned to keep note book listing setup, tune and changes.

I appreciate all of the advice. We are going to double check timing then dial in the 750 Holley a little more. If we can't get it where we like it we will bolt on a 650. Thx Andy