If you want to run over 6000 RPM a 750 is not too much carburetor for a 350. On paper it looks like its too much but carbs are really only efficient at metering fuel up to 80% of their advertised rating. Then they start to act like a flow restrictor and the internal vacuum signal gets too high for proper metering. Remember that Chevrolet didnt think the same 780 carb that they used on the 396 was too big for a 7000 RPM 302. The carb only meters fuel to match the amount of air flow through the carb so its really hard to overcarburate a 350 but its easy to undercarburate one . A 600 is too small for even a mild performance engine. A 750 double pumper is just about ideal for a 350 under 7000. Over 7000 get an 850. Yes, even on the street . Under 6000 keep the dual plane. Over that you arent going to hurt a thing with a single plane . I always though the old school original Torker intake was a great choice for a 7000 RPM small block.

 

I would use the dual plane also. A 650 would what I would use, Holley 80783C (similar to a Street Avenger 670, but jetted a bit richer) If a automatic, what is your convertor stall and gearing. Didn't remember seeing that.

 

this thread is kinda old ,but i run the 600 not 650 an 400 hp an near 500tlbs is a mild street engine the 600cfm has worked great for 3 years now with a 600 lift an 10,2 ratio

 

I agree also, running a 600 on my 77 also. Works fine for me. When I re-do the 350 in my 77 w/ a .500 lift +/- roller and vortec heads, I could start with that same 600 and see how I goes. Old thread, ok I'm done.