Holley Ultra street avenger 383

[Lewis]

Hello my carb broke the other day at its cheaper for me to buy a new one than me to fix this one,I was looking at the Holley 670cfm ultra street avenger, I have a 383 out of a coronet and it's quite tuned I don't know how tuned as I bought it not long ago of someone who doesn't know much about the car, is there anyone with that Holley that could rate it for me? Also would it be the right one? I have a 73 charger 3 speed auto with what I've been told roughly 400-450 bhp and little knowledge about carbs thanks.

[440]

I just bought a 670 Ultra Street Avenger but haven't used it yet. From what I can tell the 4 corner idle adjustment can be tricky.

Here's a couple of basic carb cfm calculators

http://www.4secondsflat.com/Carb_CFM_Calculator.html

http://www.carburetion.com/Calc.asp

[Lewis]

Ah cool, what engine is it going on with what bhp? What colour Holley did you choose?

[440]

I went with the Blue Ultra Avenger, when I picked it up I was amazed at how good it looked. It's going on a little Ford 351 Cleveland pushing somewhere around 330 - 350hp, so nothing extreme. According to the calculators my engine only requires about 530 CFM but when asking Holley tech about the 570 Avenger he said it would be too small. I personally think the 670 CFM is a tad big but Holley says it will will fine, so we'll see.

[Lewis]

Ah sweet, yeah let me know how it goes it'll be a while till I can afford a new one! I was thinking charcoal grey colour just so it matches my Engine, although the red is pretty sweet, so do you think a 670 will be okay for me?

[440]

Looking at the basic calculators the 670 might be on the small side for you. A mild 383 going to 6,000 RPM says it requires 631 CFM and a race engine going to 6k requires 678CFM. I would choose the 770 Avenger going by the advise Holley told me. Knowing your engines volumetric efficiency is a big plus....

I'm sure some of the pro's on the board will chime in with more knowledge.

[Lewis]

Okay it's hard because I don't know how well it's tuned, I was told it was rebuilt from the bottom up with loads of tuning parts but that could all be a selling point to me, I do know when I take the oil cap off its all blue anodised but that could just be it if you know what I mean so not sure I was just going for the 670 because it's like in the middle if you know what I mean

[BSB67]

......my carb broke the other day

How did that happen?  Fall out of a tree?  There has to be a good story here......

[Lewis]

Hahah no that would be awesome to see though previous owner broke the corner off the base plate and glued it back on being the fantastic mechanic he is so I need a new base plate plus rebuild kit and it didn't come with a choke so it's going to cost me about $300 plus to fix it because being in the UK I get stung by the postage so I might aswell sell it as spares and buy a whole new unit it would be easier for me

[70-500-SE-EXPORT]

I went with a 770 street avenger on my 383 and the a/f ratio is perfect. I think the 670 is too small, at higher rpm it may run lean. I called Holley and they recommended the 770.

[Lewis]

Sweet thanks, would that be vacuum secondary?

[BSB67]

I went with a 770 street avenger on my 383 and the a/f ratio is perfect. I think the 670 is too small, at higher rpm it may run lean. I called Holley and they recommended the 770.

This carb may or may not be lean in this application, but to be clear, the CFM rating of a carb has nothing to do with a carb being lean or rich.

[Lewis]

Okay, what would you suggest?

[BSB67]

Okay, what would you suggest?

I'm not sure if this question is to me?

I cannot suggest anything, as I know nothing about what you have, or what you want.

[69wannabe]

I ran a 670 street avenger on a 383 I had in my charger for awhile and it ran pretty good, I did have to jet it up several sizes on the front side(primaries) to get the lean stumble out of it. Later on I swapped the 670 for a holley 750 double pumper that really woke up the engine!! I think the 750 DP may have been a little rich on the 383 but I had a 440 hanging on the engine stand soon to go into the car so I just ran it for a little while til I swapped out the engine.