Jeep Strokers

Ok so I'm in the UK which means that somethings are not available easily etc. But this is what I have.

I have a 85 CJ5 Cali Import so rust free in the UK with the 4.2, 300 T-Case and 5 Speed on the floor box. It runs and drives, but has its issues, possibly just the carb and emissions crap.

So I also have a 96 ZJ 4.0 Parts Jeep (I have the full rig) and a 99 WJ 4.0 Parts Jeep.

So kind of wonder what is the best route to head in from here??

Am I building the 4.2 or the 4.0?

I'd buy a good carb or EFI kit for the 4.2 and sell the 2 parts Jeeps. If the CJ is in otherwise good condition, you are opening up a massive can of worms for this swap. If you have the time/money it may be worthwhile, but otherwise I would try to keep it simple.