Well, a rebuilt car. That works properly is worth some bucks. I'd put it up for at least $100, but the actual condition (looks included) can have the price vary. Roll the money over into the new carb.
(HEMI446 he said he had a purple cam.)
808 - tell us about the engine some more for a better than general carb recommendation. If it is a stock engine with a cam and a stock converter with Hwy. gears, an 850 Hoey is probably going to be to big.
The 383's did come with 600 CFM carbs from the factory. Road Runners had them Equiped ith Holley 4160 carbs. Also with Carter AVS 630 CFM models.
(I get that CFM number from the old Carter tech line.)
The problem is with those carbs is that they were on the smallish side from the factory with reason. Mostly due to the Hwy. gears that came stock. Even with 3.55's, by the time you rev it up top, your flying down the road.
On e you added headers and a cam, you really needed a 750 or better to max it out on the top end.