If you want to do an engine swap, it's not as bad as some say it is; I have been doing them for years [chevy in jeeps, chevy in fords], a 350 will fit but it is tight, best to use a 4.3, do want injection or carb? When I do a swap I keep it all one kind--- chevy motor, chevy tranny, chevy transfer case, the reason why is the adapters are around $500 if you want to try and stick a chevy to a jeep tranny. My friend an myself should have everything you need to do a swap, he builds monster mud trucks and has a four wheel drive shop. I'm doing about the same thing in a 89 comanche, 4.3-- reason you can buy one in Ocala fl. from Titan engines all ready rebuild build for around $1300. also the the bore and stroke is the same as a 350, the only thing different is the rod size, you can order a intake from edelbrock and carb. and it will run and headers from pace or hedman. This is pretty much plug and go. You will need to do some welding for engine mounts and tranny mounts. If you want a very easy drop in, get an older jeep j-10 or cj with a 258, tranny and case, [get the whole thing if you can], this is a drop in for your comanche, this is a no frills set up, carb, points which can be changed over to a chevy hei dist. You do not have to worry about o2, crank senors, map, tps, etc..., just a couple of wires for the starter, one for the dist. hook up the alt. and go for the most part.
Shot me an e-mail if you need any parts. HooksNfeathers@aol.com , I'm in the homosassa area.