I have a 1982 D-150 with a 225, (Offenhauser intake, Holley 4bbl, Mopar Perfomance Ignition, Clifford Header) OD 4 speed, and an 8-3/8 rear end with 3.20 Gears. I want to change to a better gear ratio, and put in a posi unit. I was told that the 8-3/8 and 8-1/4 rear ends were identical except that the 8-3/8s were given a larger ring gear for increased lods in vans and trucks. If this is true, can I order a set of 3.55s, a Sure Grip, and an install kit for an 8-1/4 and put it all right in? It is IMPOSSIBLE to find stuff for the 8-3/8, even with the junkyards around me. Thanks for the help.

i know the gears are interchangeable on the early 8 1/4, 8 3/8 rears from an old mopar action article, but there is a year split somewhere in the early '80s where the new diffs are different. try randy's ring and pinion or some 4x4 guys. the 8 3/8 should be a fairly easy axle to get stuff for as they are under most jeeps.

-james

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