What is the correct size carb for a stock 383 Magnum? I know for an automatic car it was a Carter AVS, just not sure what size.

Thanks!

It was a Holley on 1970 383 magnum. Not sure whatnsiz, primaries small, secondaries larger. A 440-350 horse Holley carb has all bores the same small size.

Wasn't the Holley on manual cars and the Carter on automatics?

For a 1970 Challenger R/T 383 auto with A/C you need a Holley 4369. For 1970 383 e-bodies, the AVS was basically used on non-R/T JH automatic N-Code Challengers (and BH Barracudas as well). JH and BH 4-speed N-code cars got a Holley also. There are known exceptions to this, as well as a story that due to carb fires with the Holley a lot got replaced with the AVS, but generally a 383 R/T or 383 'Cuda never got an AVS originally.

For the correct Holley list# you need to provide more info, and an SPD if you want a proper date code range. Can you post a pic of your fender tag or broadcast sheet? As far as your original question, the cfm size, they were small carbs, ratings vary, 500-600cfm range is pretty close to reality.

I'm not worried about date code and such. Car is a '70 Challenger R/T SE N code 383 auto with A/C. Original 383 is gone. 383 in car was rebuilt to stock specs, but the carb needs work. Wanted to know so I can tell if it has the right carb on it or not before I decided to rebuild or replace it.

If you want to give yourself a headache reading through it all, everything you ever cared to know on the subject is in this thread-

https://board.moparts.org/ubbthreads/ubbthreads.php/ubb/showflat/Number/4326319/site_id/1

That post was toooooo much! Ugh.

Time to build the 440 I have sitting in the back of the garage! LOL

The original 383 to the car is long gone and the replacement 383 in it now is orange, has a Holley on it, and log style exhaust manifolds. The car is not 100% correct/original, so I will take certain liberties and do what I want with it.

A "stock-ish" 383 will perform best with a 600-650cfm Holley in my opinion. The 600 vac secondaries are cheap. Don't use a double pumper & a 750cfm is too much. I have run an old Carter Competition Series 500 cfm on a 383 & it ran good, I just think I was missing some top-end.

Anytime you look at a Carter AVS , just turn it over and look at the throttle bores
If all four bores are the same size it's a 750 cfm

If the primary bores are smaller then the secondary bores it's a 625 cfm

Carter AVS 625 cfm was found on the 383 Magnum HP motor if it was coded for a Carter AVS

Carter AVS 750 cfm was found on the 440 Magnum HP motor if it was coded for a Carter AVS

You might find a Carter AVS 625 cfm on the Non HP 440 motor

Standard 70 Challenger (not RT) with a four speed 383 had the Holly, I had one in 70. One year only carb, different from the 440 carb. Might still have one of each.

Holley rates them at 585 cfm

YIKES!

I remember that one.

That thread just reinforces how much guys like Randy (Wild RT) and Joe (Beep Beep) are missed on here.

I was fool enough to read that thread. My head is still spinning.

I remember that thread also. I was on here more regularly back then.



Beep Beep was always a great source of info. Snoopy also. They are both missed.
What happened to Randy? He was always super helpful.

You're pretty important around here also!,...and Dan and Barry and Terry and so many others. Moparts is a great forum!

Tav