670 cfm or 770 cfm?

[reddog64]

which cfm carb should i go with?

30 over 350,
flat top pistons
76cc chambers
comp cam 268h
performer intake
dual flowmaster exhaust

looking at the holley truck avenger off road 670 or 770...

 

[4X4HIGH]

670 will be perfect. The 770 will be too big.

 

[reddog64]

Thanks,
I decided to search and that was kinda the recommendation... 770 is too much...

 

[Oilbrnr]

Why not go FI?

A guy was selling a 670 on Craigslist down here last week for $100. I almost went and got it, but when I asked him why he was selling it, he said that he could never get it to run right and went back to the original Quad. Now I know that I could get it to work right, but I figured I'd rather put the money towards a FI conversion.

 

[reddog64]

I found a guy on CL selling a 650 for 125 so i'm gonna go pick it up on saturday...

 

[southernspeed]

Yeah as 4x4 says, 670. I'm using a 770 street avanger on my wife's tuned 454 Camaro and it's perfect.

 

[rcamacho]

670

 

[rcamacho]

Yeah, Holley carburetors are generic and modular. They take tuning on any specific engine/drivetrain combination. Just a little knowledge, reading, trial and error.

 

[Rhino6678]

725CFM demon weve got about the same set up for motor.

 

[think_07]

I had the same question a while back, I'm building a pretty mild 350 also and didn't know if I should go with a 670 or 770 because all the builds I found used a 750 cfm carb. Everyone I talked to suggested a 670 truck avenger for the same motor that would use a 750 "regular street type" carb. I'm not exactly sure why because I also thought a 770 would be the way to go, but I guess not.