I have a 73 Camaro with a sbc400 engine with an Edelbrock performer intake and cam (not rpm), and now I want to replace my actual carburetor, but what could be the best size? and brand? I think in a Holley street avenger 670cfm, but don't know if could be a little small or could be good. Help please.

 

What else do you have working with that motor...

 

that 670 is probably a little small, what kind of driving do you do?

 

This is my week end car. I only use her for street and ocasionaly to drive any travel of about 600-700 milles (two or three times a year). My preferences are not a good time in the 1/4, but also are welcome . I look for a good relation power-mileage.

 

Might I suggest a Jet Q-Jet. Its the best bet for mileage, throttle response and good wide open performance. Fine tuning parts are available from Edelbrock still. The Jet is rebuilt and tuned for mild performance engines.

 

under most driving conditions the 670 will work very good. Only if if you wanted max performance should you move up in size, but this would cost you some everyday drivability. I personally ran a 600 holley on a 400 in a 89 Silverado with very good results.

 

Dual plane manifolds have shown repeatedly that they realy do like a bigger carb than you'd think. With a good set of headers I'd try an Edelbrock air gap manifold and a 770 street avenger carb. JMO

 

Well...I gotta disagree. With carbs bigger isn't always better. I have a 406 sbc in my 76 Laguna that makes in excess of 500hp. I used a reworked AFB 625 carb. I've never had a problem leaning out or with adequate fuel delivery. I have tried other carbs, both bigger and smaller and only switched after Super Chevy tried a 650 Mighty Demon. I use an RPM Air Gap. Also, Super Chevy passed 500hp with a 350 using a 650 Mighty Demon and a Victor Jr. intake (Spring 2004; Volume 33, No. 4; Pg. 94-98). Like I said, after that article I switched to a 650 Mighty Demon. I'm sure people will disagree with me, but there are dyno sheets to prove you don't need that much carb. I don't have a dyno sheet for my car, but I do run 9.80's in a stock body car. It weighs nearly 4700lbs.

Zach

 

I agree with the above post mentioning that a dual plane intake can use a larger carb without hurting low end performance. A 400 theoretically with 100% volumetric efficiency needs 700 cfm at 6000 rpm. I ran an Edelbrock performer 750 on my 406 and spun it to about 6600 with great results. It's a really simple carb based on the Carter AFB but has a few upgrades that make it work extremely well. Yea, I fooled around with a Q-jet and 3310 Holley but never could get the throttle response I got from the performer carb. Best part of all is they are cheap! Low 12's in a 71 Caprice with 1.68 60's.

 

I've read several articles that state these carbs (Demon) flow more than their rated. So, in essence, you are actually running a larger carb.

 

we used to have a holley 750 on our mild 400 and it worked great.

 

The reason for the flow differences is Barry Grant wet flows the Demon while Holley dry flows their carbs.

 

I'd say go with a performer 600 or 750, I had a 750 on my Galaxie until my friend gave me the thunder series 800 when he blew up his 454. also wanted the extra flow for when I put spray to it.

 

I personally use a Demon, and have many friends using Demons of various types. No complaints at all from any of us. I recommend them 100%!!!

Zach

 

Either a stock/rebuilt quadrajet (750cfm) or a holly 650 or 670.