Is 770 CFM too much for a 304?

[craigparrish]

I found a great deal on a holley 770 truck avenger. I've got a 304 .040 over with an edlebrock performer cam/intake. pistons are mild TRWs. The rest is pretty much stock. What problems will I get from the 770 CFM? Should I stick with a 670?

[jeepsr4ever]

[craigparrish]

Is that a vote for or against the 770?

[jeepsr4ever]

yeah, thats a little much my friend. But as we all know it depends on you jet size

[tufcj]

I'd say it's a little too much, even for a built 304. If it has vacuum secondaries, and is jetted properly, it could work. The bigger the primaries are, the more sluggish the throttle response. Small primaries make high flow and crisper throttle.

I've actually used 390-450 CFM carbs on 304s, and they worked very well. I only used a 650 on my built 360, and sometimes that was too much carb. Bigger is definitely NOT better when it comes to carbs.

There are formulas to calculate needed airflow, I'll post if I can find it.

[MNTrailBoss]

I have the smaller Truck Avenger on my 360. Plenty of carb for that engine. Probly only makeing 195 - 200 HP with it anyway.

[rollen dean montoya]

might try going with either a 570 or 600 cfm max. just my 2 cents
worth
later, rollen

[thigh19]

It really only depends on what you're planning to do. I ran a 780 holley on a 304 with a tunnel ram, wild cam, headers on a mud bogger and could have used more carb. My 401 didn't like the 600, but really woke up with a 750 on my J10. I look at it this way, the engine will only flow so much, start big and jet down. Cheaper than going from carb to carb and easier too. Just my 2 cents.

[jeepsr4ever]

Just to clear things up 700cfm is just the max air flow not the fuel amount going to the carb however if you run a large jet size and the primaries bores allow too much air in you will never get a idle without stumbling. I would run a 600 or 650 (DP) tops......BTW any updates on this one?

[Lifted79CJ7]

I have a brand new Edlebrock 600 cfm (ran it on my 401 for 20 minutes) with an off road needles and seat kit already installed that will be too small for my 401. I originally bought it for my 304, but ran across the 401 for a good price, so decided to rebuild it instead. Wanna trade? Not sure what those are worth, but just a thought.
Jack