4.2L

[RoXJok]

So there's a guy who's selling a 4.2L out of a '81 CJ Scrambler. What is/is not interchangeable as far as my curretn 4.0L? Just wondering if this would be a good candidate for rebuilding and dropping into mine.

[stewie]

i hear that the crank can be used in a stroker. does that count?

i am using a 4.2L serp belt on my xj after deleting the mech fan. the belt is for an 83 (full size) cherokee 4.2 without power steering.

[Gasman]

In a nut shell, no. Not a good replacement. Those 80's 4.2's are low revving smog dogs. The heads suck, you would have to switch to a 4.0 head to use your fuel injection. IIRC, the 4.0 head has water passages that don't quite line up so they have to be welded closed, etc. Not a direct bolt on job. It would really be a step backward IMHO. Better off rebuilding your 4.0. As Stewie mentioned, you could use the crank and rods out of the 4.2 to build a stroker. I can't recall what year 4.2's are the best for the donor crank though.