RE: What carb for 71 383 magnum?
I have a '71 Superbee with a 383. When i got the car it had a Holley 4bbl, vaccum secondaries. It was a 600cfm. It worked well in stock form. I'm not 100 % on the originality, however i was advised by a couple knowledgeable Mopar owners that many '71 383s came with Holley 4bbls. You may want to closely examine the spark plugs to see if it is running too lean. if the engine is stock, more than 700cfm is too much carb for your engine. 600-650 sounds about right.