4.0 AX15 vs AW4 and 93 EFI

So, I have a 93 2 door parts vehicle 4.0 5 speed.

My son is getting ready to head to college in his 87 2 door Chero and has been using to tote his friends to Super Smash Brothers Tournaments all over the state and then some. As you might imagine, the biggest complaint is the mileage so I am considering some upgrades.

So I thought I would swap in the 5 speed from the 93 (along with the necessary Renix ECM) . THought that might be worth a couple of MPG's.. anyone with real world experience?

With almost 300,000 miles I am likely going to be rebuilding one of the 4.0's I have in the shop. THe engine reman place I sell blocks to says he does NOT want the Renix era blocks... I was not aware of any difference between those and the early 90's blocks.

THEN I thought... I wonder how difficult it would be to upgrade to the MPI system currently on the 93... not sure if that would be worth it, but since I will be rebuilding SOMETHING maybe that will not be a big deal?

Your experienced insights are appreciated!

Jesse


I also considered using converting

As renix doesn't have a cel, I would just swap the 5 speed and corresponding parts, disco / remove tcu.
The renix system handles mods better than the Chrysler efi. I wouldn't bother swapping all that.