Mopar #'s Matching

man, that is a bare bones tag~ see the 31, thats a 273/4 and the 55 is an auto with heater. if you got the original 273/4, take the cam and intake and heads and put them on a 318. I did when I spun a 273/4 rod bearing and never looked back. It was faster as a lower-comp 318 than it was as a hi-comp 273 with the 4bbl intake and camshaft. Youll need a convertor ring for a later crank on an early trans as the crank convertor snout sockets were bigger in 68 crankshafts, just a 1/8 thick centering adapter ring.