rayray

I'm getting ready to order carb. for my new 383. I'm thinking of using a 770cfm street avenger. Has anyone used this type Holley? And how do you like it? I'm using a air gap intake on my '71 do I need anything special to hook up the linkage for the gas pedal? Thank Ray. :chevy

Aaron-74

I've yet to hear ANYTHING bad about the Holley Street Avengers. I'd REALLY love to have one. but my 4160 is fine.

Paul 75 L82

Go with the Demon, even Lars will say that you will pick up some horese with the Demon.

1980ZZ4

If I hadn't had the opportunity to get my 750DP free (new), I'd done the Demon for sure. While I also haven't heard anything bad about the Avenger, the Demon will suredly create more HP. Good Luck.

Chucks76

I am running the 670 Street Avenger. It replaced a 600 Holley that I couldnt get to run right. The Street Avenger is much better IMO.

GWHITE75

If you're going from a stock Rochester to a Holley or Demon, you might need to modify the pedal cable mount to the carb. Also, you might want to check with Holley or Demon and see what CFM size carb they recommend for your car. The 770 might be too big. Holley offers a simple formula in their book to calculate the needed size:

Cubic Inches x Max. RPM/3456 = ?? x .85 Volumetric Effeciency = ??? CFM

It seems to be pretty accurate for modified, normally aspirated street motors.

bigvette1

I have a 73 454 and am running the 770cfm averger. It worked out of the box with just a mild tweak on the idle. I did have one problem of a slight bind returning to curb idle. Much looking and feeling and I saw one of the primary blades scrapping. Loosened up the screws slightly with the engine running and let it find its own seating, tightened it up and no more bind.

I work with a super engine building shop and here is what they say - the only tweaks are the springs in the secondary and these things make real power on the dyno. Try one!

norvalwilhelm

I know nothing about the avenger but I would choose the carb with adjustable screw in air bleeds. Getting the idle mixture right is a problem. The Demon does have the screw in air bleeds so that would help me make the decision.