need some help with a 4.2L swap

[bigoltrux77]

Im interested in swappin out my aged 2.5L to a 4.2L from an early 80's CJ. Is this possible? Will it bolt up to my ax-5? If not how can i swap in the t-4 and maybe an np231? Any help is appreciated. Thanks

[CW]

My advice is to get an old 4.0l block and use the 4.2 crank and rods for a stroker. But, if you go with the 258 a HO 4.0 head is an awsome upgrade. I "think" that everything should bolt up.

[bigoltrux77]

btt

[Eagle]

The tranny will not bolt up. The 2.5L uses the small bell housing bolt pattern that matches the GM 2.8L V-6 engine. Also, since you have a 207 transfer case, you obviously have an 84, 85 or 86 XJ. The engine compartment is too short for the I-6 engine. You will have to replace the radiator supports and modify some sheet metal in the nose, as well as "massage" the firewall/floor pan a bit with a large hammer. This swap can be done, but is not recommended.

[bigoltrux77]

damnit! alright thanks for the info...i almost spent my money on a bad ass 4.2L

[bgcntry72]

Your best bet would be to find a Bowtie 3.1 or 3.4 in a yard from a Camaro, etc.
This will bolt right up, almost.
Look for a 60* v6.