A Holley 4160 is factory correct for the '71 383 motors. Mine has a 4668 carb on it now. According to the shop manual the 4668 carb is correct for a '71 383 Automatic. A Holley 6191 was specified for the 383 4-speed motors (B&E body). From what I have read, a lot of these Holleys were replaced by dealers with Carter AFBs due to leakage problems. Mine is leaking around the secondary bowl and transfer tube. Hopefully some new gaskets will solve the problem.

Mine is also missing the choke diaphragm link so if anyone has one, let me know. I am going to try to bend from 3/32 welding rod based on some pics I have--maybe I can get close enough to have an operable choke--you really need one in Montana.