My YJ is the last year that they made the 258. I put a 96XJ head and exhaust on it with the mopar EFI kit. 30 over with a HOT cam(clifford 272). It will spank most. Lots of $$$ tho.rokbrkr said:I had a '79 CJ-5 with a 258 and T-18 4 speed, ran great right up to the day the ring stuck, and then it just smoked too bad to drive it
So I rebuilt it............had an offenhauser 4 barrel intake with a motorcraft 2 barrel adapted sideways, torque cam, dual exit headers, shaved head for more compression......I wish I still had that motor, it would keep up with stock V-8's, and out ran a worn out 302, I would have to wonder if it would have power enough to pack a full size waggy around very well, but it worked great in the light wieght CJ :thumb:
It is a step up, but the old renix system is pretty crappy. I would not deal with the headache of the swap to that system. Just too much work for a poor upgrade. The most helpful thing that I did (prior to MPFI) was make an HEI distributor that I wired in there. It ran really good and I disabled the stepper motor on the carb. It ran pretty good. I'll see if I can find my diagrams for the wiring. I still have the HEI that I built too. Could easily separate from it for a nominal price. :thumb:AH said:On the same subject. I have a 90 yj carb'd 4.2 and an 87 efi 4.0. If you had to choose between them for the yj which would you put in? This came up a bit in another post but I am just wondering.