cj engine/year question

[nocturn77]

Hi all, Im a newbi here and am looking for my first jeep.I wanted to do some research first and figure out which year would be best to look for. I realy like the CJ's,so I started looking and found a 1979 cj with the favorable T18A transmission.But I got a little ahead of the game and started looking into upgrades for future reference, and noticed things like the aluminum valve cover's only offered for 1981-1986. and also the fuel injection mopar MPI only for 1981-1990.
what gives? is the 4.2L different from 1976-1980 to 1981-1986? can you not do a 4.0L head upgrade with the MPI on say a 1979 cj?

 

[jay79cj7]

There are some differences between the <80 and >80 258's. I don't know all the details, but I have a '79 and have found some of the same things you have. The earlier models came with a metal valve cover, and the later ones came with a plastic one. I think the reason alot of people want the aluminum cover, besides looks, is to replace the leaky plastic ones. On an older 258, you don't have that problem. Also in the older 258's you don't have the pulse air emissions (or at least mine doesn't anymore), and you don't have the crappy computer controlled carb, which I understand to be good differences. Seems like there are a few other differences that I have come across, but I can't think of them right now.