Over carbing?

[lukieg]

 Hello all.. I went to one of those online cfm calculators...  Im building a mild 305 for another project and I dont expect it to ever go beyond 4000 rmp... just cruising and a bit of pulling.. It rounds out to a required 300 cfm... thats it...  so a holley 390 should suit it fine?? Seems small. Thanks

[ohio hab]

This sound's right, for an street truck I find better to be on the smaller size than larger size, for throttle response. An larger carb on an race truck, because the engine is staying at higher rpm's. Smaller carb better down low, bigger carb better and upper end.

[1980c10]

I'd go somewhere between a 500 and 600 cfm

[Irish_Alley]

I'd go somewhere between a 500 and 600 cfm

this is what im thinking but i would also trust what the maker of a carb says

[1980c10]

I ran a holley 600 on a 4.3 v-6 (262 cid) it ran perfect in stock form. With a 600 cfm you'll have plenty of vacuum. If it is too big it can be jetted down but I doubt you'll need to do that. If someday you build an engine; you'll be able to re-use it with bigger jets and if you decide to sell it later on you'll have a better market.

[lukieg]

 I might just go for a stock qjet.. those things are amazing... I took one from a 305 and put it on a 366 td once.. ran perfect.. likely because the tall deck was shifted at a max of 4000 rpm.

[autorepr]

Edelbrock has a performance Q-jet I've heard good things about. (as far as light performance)

[joesgarage71]

I might just go for a stock qjet.. those things are amazing... I took one from a 305 and put it on a 366 td once.. ran perfect.. likely because the tall deck was shifted at a max of 4000 rpm.

Yup X2