Looking for some guidance.

[jimbos76cj]

I currently have a motor dilemma.. I currently have

1.a complete 4.2 with RV cam and long tube header that I've heard Kinda run, it was taken from a rolled YJ and started on ether. It started, sputtered but didn't knock of sound horrible considering the circumstance. Accordining to the PO it has about 10k on a fresh rebuild. Normally I wouldn't belive it but he was a member of my local Jeep forum and seems to be right.

2. a 4.0 motor that the PO says is complete and say only 6k miles on it. again seems to be a legit guy. Say he pulled it to put a stroker in his YJ. Its a complete motor with a 7120 head. He can provide documents from the rebuild.

3. A complete 360 that needs to be rebuilt.

I was originally going to throw in the 4.2 and just drive it. but now with the 4.0 coming into play my mind keeps going into stroker mode!! If both motors are as good shape as the PO's say they are the machine work should be next to nothing so my cost would be gaskets, bearing and piston rings. then I keep questioning will the carbed intake fit on the 4.0 head? and would the stroker really put out more power then the 4.2 with a cam in it? I'm also a little confused at the need to get new pistons.. can I just run the stock ones or will that put my CR to high causing it to knock.

then the 360 keeps sneaking into my mind but the thought of new motor mounts, plus the machine work and new parts make me shy away from it. Plus I want something thats not going to destroy the ax-15.

lastly if I were to use the stock piston and run propane in it (110 octane) would that take care of the knocking issue with the higher compression.

[SilverXJ]

and would the stroker really put out more power then the 4.2 with a cam in it? I'm also a little confused at the need to get new pistons.. can I just run the stock ones or will that put my CR to high causing it to knock.

Even the 4.0L will put out more power than the 4.2L. You would have to have the 4.0L pistons pressed off the 4.0L rods and pressed on the 4.2L rods. There is a good chance the pistons will be damaged while pressing off.

then the 360 keeps sneaking into my mind but the thought of new motor mounts, plus the machine work and new parts make me shy away from it. Plus I want something thats not going to destroy the ax-15.

A stock 360 will not have enough power to destroy an ax-15.