Will a 570 cfm Holley Street Avenger be a good carburetor for a mild 350 Chevy? My motor has 9:1 CR, 882 heads, Edelbrock performer intake, 218/224 .442/.465 cam, L-98 manifolds and a stock speed TC. Will this flow enough air for a daily driver motor or should I go bigger? My car rarely sees 5000 rpm. TIA.

 

Probably too small, a 650 is more like it.

I personally think the Avenger series is overpriced. You can get a "standard" electric choke VS carb, add the quick-change secondary spring kit and secondary spring assortment, get the 4150 conversion and a full set of jets, and a Holley tuning book and the see-through flow bowl plugs if you want, all for less than what the Avenger alone costs. What you'll give up is 20 cfm of flow rating (if it really is a sacrifice), and one vacuum port that you probably won't use, anyway.

What you'll gain is a more tunable carb while having spent less money.

 

A 350 cubic in. at 6500 rpms, 85 % effic. = 560 cfm .

 

if you'll notice, I said I rarely turn 5000 rpms. i don't care what the volumetric efficiency is at 6500 rpm.

 

See https://www.thirdgen.org/techbb2/sho...hreadid=10705, the first part of which is Jester's blowing-out-of-the-water of the "standard" formula.

A 570 would be "okay" for a street driven 350. It just won't have the punch you'd get with a larger carb if/when you want it.

You have quite a bit of cam for an engine that "rarely sees 5000 rpm".

 

I like the S/A carbs. Easy to use basicly a holley for dumbies I have the 670.
From what you put in your car I dont think that would be waht your looking for in a carb. If you want a lower CFM carb go with a 600 (80457S) Its a good carb and a heck of a lot cheaper than the S/A carbs.
SSC

 

LOL pretty much it the 670 was my first carb purchase so I just wanted something to slap on the car and have everything I needed. Runs great on my 305 Next one will be a 750 double pumper though for the 350

 

You missed my point,if it has enough cfm for a 350 with an effic.[the eng.; not the carb] @ 6500 rpms ,then it is more than enough for your engine at 5000 rpms.

 

oh, I see what you were saying. I didn't mean to come off as having an attitude. Sorry bout that.

 

If your main interest is economy and driveability, then a smaller carb will do you fine. It just won't have as much umph when you do want to get on it. If you're willing to sacrifice the umph, a 570 cfm will do. For that matter, a 450 cfm would do.

I still maintain the Avengers are a waste of good money. A 600 VS electric choke with the add-ons I suggested above would be money better spent, in my opinion, and provide the tuneability you'd need to get the best economy and driveability out of it.

Also, in my opinion, if your main interest is economy and drveability, your better bet would be a q-jet, specifically a CC q-jet.

 

I ,m in agreement with 57kid,a 600 cfm holley universal would be cheaper and easy to find on the used market. I also agree than a Rochester[properly set-up] can't be beat for acombination of economy and power ,but it's important to get right Rochester for your engine. If you are non-computer get one from: 70-77 chevy truck w/350 or 70-75 full size chevy, camaro or nova w/350.

 

I have a 1969 quadrajet from i think a chevelle. Ive researched it a bit and people have told me its a good performance carb, especiually for use with a bigger cam. I think I'll put that one on the shelf for now and just stick with my computer setup for now and switch it later if Im not satisfied.

 

Welcome back from the Dark Side. The much-malingned CC q-jet is not a bad actor per se. Misunderstood, perhaps.

FWIW, for out-of-the-box driveability and performance in a square bore, the Demons are really the way to go. Wish I had done that with the '57, but too late now (not going to go getting another carb - gears are more important). They are in the same price range as the Holley Avengers, so no using that as an excuse.

You're on the right track now. Tune that CC q-jet, and you'll be happy.