383 2bbl vs 383 4 bbl

[sthorvictor75du]

i was planning on pulling my 383 4bbl and dropping in a 383 2bbl (im converting to 4 bbl) that is currently sitting in a polara, both motors are out of 69 cars, the 4bbl was stamped H in the vin in the newport with the HP manifolds, all i know about the 2 bbl is that it runs, doesent smoke knock and has good oil press, and the exhaust manifolds are a different shape, what i dont know is what really makes the two motors different besides the 2 bbl or 4 bbl?? ive heard the 4 bbl has higer compression and other stuff from other ppl and others im getting different oppinions, i would like to clear things up before swapping them, and decide to tweak one or the other so to say,

and has any one tried turbo's on a 383???
thanks

 

[68383GTS]

The compression is abit lower on the 2 bbl motor.The cam,intake,carb,and manifolds is about the only difference.I had a 70 383 2bbl Fury.I tuned it up and put a 4 bbl carb and intake and it ran really well.
Jim

 

[demon sizzler]

All 2 bbl 383's had dished flat top pistons. Only the '68 and '69 383 4 bbl, hp and non hp had the tallest piston to deck height. It appears that your H code 383 is an hp engine. So it would have the following additional differences to the 383 2bbl:

crankshaft windage tray,
hp cam(same as 440 hp),
hp exhaust manifolds,
hp single valve springs with inner damper,
tri metal main bearings(383 2bbl tended to have babitt mains)
but I have done several 2bbl to 4 bbl intake/carb swaps on 383's and they run
just fine, David.

 

[KP]

I have a great after-market single-plane 4 bbl intake 4-sale