I have an 88 Yuppie J. It has a 4.2L 258, BA10/5 French krap, stock NP231J T-case, and stock Dana 30 and 35 diffs.
What I'm looking to do is swap these things out for good junkyard stuff. I want to keep the 258 and install a mopar fuel injection kit, then mate it to an NV4500 and NP231D from a Dodge.(I know it's from a newer Dodge but what year(s) am I looking for?) Will they mate with a bell housing adapter, would there be any shaft or clutch problems? Need your input.

Call Advanced Adaptors or visit there web site for info.

It would be cheaper to get a complete 4.0 or at least the head and injection then getting the MOPAR kit (which is just all the parts off a '93 4.0) This would give you the better head design of the 4.0 also and maybe even a lower milage short block.probably just back that up with the late model 5-speed and a 4:1 kit in your 231. This would give you almost the identical (actually slightly lower I beleive) 1st gear low range ratio and more then likely save alot of money.

[ 09-04-2001: Message edited by: SquirrelMaster ]

Or for that matter, now would be an opportune time to swap in a Ford 5.0 or Chevy 350, or just about anything MPI. If you're doing the MPI swap, you're looking at $2k easily. Why not spend all that on an injected engine with more horsepower. Heck that's over halfway to a Ramjet 350 which would be plug and play!