holley 670 street avenger jetting questions

[SirDan]

Anyone have experience with the avenger series of carbs?

not on a mopar but looking for advice. ford 351 Cleveland 4 barrel heads (which essentially have big block sized ports) cams like 550 lift, eddy intake i forget which one exactly. Basically just simple bolt ons. It sat for a while but got started occasionally and moved around a few times and ran great every time. Finally got it back on the road and my father bought a brand new 670 street avenger for it bolted it on. It starts up and cruises down the road fine, But this car is seriously down on power. Hitting on all 8 wires in the correct order, timing is around 12-14 initial 36 total all in around 2k rpm. It just doesn't have half the power it should.

Now after that I bought a 670 street avenger for my 302, roller cam motor with intake cam and exhaust. nothing too wild but has a nice lope. Now this car I have an air fuel gauge in, the carb runs pretty good all around but when you have it floored it runs about a 13.5-1 air fuel ratio. Keep in mind this carb is recommended for 300-400 hp at best this motor makes 300hp and is on the small side as far as cubic inches are concerned.

In short I am thinking the carb is pretty darn lean out of the box and think I need to jet up on the 351 to solve the no power issue. Anyone else have similar issues with a street avenger?

 

[subcom]

I'm running a 770 avenger on my 360 magnum. It was running really rich out of the box but otherwise is a reliable carb that delivers good power. I took a look at the front jets today to drop them down a size or two to bring down the richness. I expected to find #70s which is what they are supposed to ship with. Mine had 72s . Maybe yours is jetted on the lean side.

 

[OldmanRick]

Hey SirDan, hope life is treating you good :thumbrig:.

I don't have personal experience with the Avenger series, the're after my time. But I have recommended them in the past.....maybe by mistake, especially the 670. I've seen others have what seems to be a lean problem also, but I just attributed it to the mild jetting they come with, or the secondary opening spring needed to be lighter. After further review, these carbs have the same size throttle bores/venturi size as a regulation 600 carb.

I gave Holley the benefit of the doubt as far as stock metering was concerned, but maybe the 670 just acts too small for the rating they gave it.

I love the 4bbl Cleveland! I'm betting it just want's more carb?

Keep us informed on what you find...

Take care, Rick

 

[gliderider06]

They are jetted lean. I have one and came with 65 primary 68 secondary. So far, I have 70/74 in them and a lighter spring and it runs much better, but still needs some more tuning.

 

[straightlinespeed]

Ive had awful experience with that carb. I've tried everything I could to get it to work on my car, moderately built 360. I've tried jetting it up, down, changing the power valve, squirters everything! I could not get it to perform at all. I got to try a quick fuel 750 carb for free and I had no issues at all with it.. Ive heard some people have had good luck with those carbs and others like myself cant get them to work at all.

I will say that yes the 670 comes with 65 primarys and 68 secondaries. I bumped mine up to 69's to start with on the primaries and 70 on the secondaries. Like I said though sadly I couldnt get rid of the bog it had when you went to WOT, so I got rid of it.

Best of luck and hope you can get this carb to work for you.