basically ive been wondering if my 650cfm holley is enough to feed my 305 now that i have a weaind 142 blower, ive been looking at 750 hp series but i dont want to spend that much if i dont need to, thanks for any help

http://www.summitracing.com/parts/HLY-0-80592S/

this will be all you need

the last time i went to the track i tried a 600 holley i had at my shop, and i lost .4 in my et and 6 mph, even after jetting it for the most mph, thats why i was thinking i might need a carb bigger then my 650

did you run that carb with the roots blower? all that vac is keeping the powervalve open.............with a roots blower u need a powervalve referenced carb for the supercharger

On a roots type blower application I would run a larger carb. Anything smaller can cause a vacuum under the carb which will cause issues. We run a 1000cfm on a built little 331 ford and a 177 on it. I would run around an 850 or even a 950, the blower will tame it down.

yes i ran the 600 with the roots blower, i block off all the powervalves and jet it up 5 sizes, irocfast do you think a 750 would be large enough

I run a 700 on my 142 on a 350
I called holley and that is what they told me was matched to the supercharger
I think this is what I got
http://www.summitracing.com/parts/HLY-0-80572S/
I would guess a 750 would work also

A 750 would be much better than the 600 and would work fine in a street/strip application. If your 600 is a DP, you could switch out the main body to give you a little more air. I think I just read an article that the 600-650-750 all use the same baseplate.