what carb?

[mopower04]

ok guys, next step on my 440 build. got the motor in the truck finally now lookin at induction. holly 4bbl 750cfm or the 770 cfm street avenger are the two i'm lookin at. both vaccum secondarys figured that would be good for both on and off road use, any thoughts on the two and why the 20cfm may be better?

[AdamR]

I would go for the most cfm myself.jmo

[4eyes]

imo depending on the cam both r tuneable i like 750 unless your buzzing the motor high rpm alot i c no need for 770 although the diff is very small if your looking to optimize 750 imo. the extra 20 cfm could add up to a small boost in hp but little or no gain in torque and a possible drop in torque. this al depends on the combo

[hotroddave40]

I had the 770 street avenger on my 318 and it ran fine. There is no 20 CFM differance. They should have the same CFM rateing, they use the same main body, venturies, and the same throttle plate so no differance in the two. The only real differance is the secondary metering plate instead of a metering block. If you like fooling with the secondary jets then get the street avenger, if not get the cheaper one.

[crisser]

Run the 750. It has more agressive idle and transition circuts than the 770.
As stated above, the 770 flows no better than the 750. Holley changed the pressure drop ratings to be more competitive with Barry Grant, Quick Fuel etc.

[Rug_Trucker]

I'd get a Thunder series Eddie. 800cfm. I read those Street Avengers need lots of mods in some instances. I knew of one on a 383 when I was in Florida that was idling pig rich. They had to change the air bleeds and tinker with some other stuff. He had a 509 MP cam.

[mopower04]

ya i from what i understand the 770 seems like it is more work. the engine is going to be in mud runs and what not so rpms will be seen but only to 6000 max. the 750 seems like it would be fine, but i've also wondered about the eddy carbs. not many people run them and i dont know why

[Rigormortor]

Originally Posted by mopower04

ok guys, next step on my 440 build. got the motor in the truck finally now lookin at induction. holly 4bbl 750cfm or the 770 cfm street avenger are the two i'm lookin at. both vaccum secondarys figured that would be good for both on and off road use, any thoughts on the two and why the 20cfm may be better?

With a 440 and any performance work you would want the most CFM's, I would go with the 770 cfm.

There is a formula to figure out the cfm's you would need, multiply the Cubic Inches by the max rpms and divide by 3456..... so 440X6000=2,640,000/3456=764 cfm's

[ehostler]

That formula only gives a ballpark number. I've run a 383 with an 850 TQ and the engine loved it.