My 90 v6 had 5 lugs and 91 had 6 lug 318. The 6 lug is easy to convert to 5 lug till the new body came out in 97.

I have a super clean 2wd ex cab 92 318 I would consider selling, I don't want to give it away and they are not worth much here so I was just planning to keep it but it is really nice and could drive anywhere.

Really to do a gen 3 swap I think 08 and up would be easiest because the 4.7 computer, harness and trans can be made to work, don't know how you would make it all work on the older ones without standalones trying to get along with the stock one to keep gauges and stuff all working. I think there is plenty of room in any of the engine compartments for a gen III. The one he has in this picture is the smallest engine compartment as 91 they at least lengthened it a little to accommodate the 318.