2000 XJ vs TJ 4.0 Block

So after putting in the new oil pressure sensor on my 2000 XJ the oil pressure is reading exactly the same. About 25 at 2000 RPM under load and 10 at hot idle. I think it's on its last legs so I'm working on plan B. I'm going to purchase another motor and rebuild it. There are a couple of reputable machine shops in the area and I can do the assembly and swap myself. Considering a stroker but I think I'll do a stocker with this one and then use the motor that's in the Jeep now for a stroker somewhere down the line.

I just found a 4.0 out of a 2000 TJ with a blown head gasket. It's dirt cheap and I know that it could have a cracked head. Does anyone know if the block casting for a 2000 TJ and XJ are the same? I want to know if all the accessory junk will bolt up or will I have to start swapping in a bunch of TJ stuff...

By the way, my local salvage yard looked it up: The 1999, 2000 and 2001 XJ block and head should be a direct swap. The heads from any 4.0 from 1999 to 2005 should also drop right on. That ought to give me a little more wiggle room if the head is cracked.

Block? Should be the same number.

The head may be different - depends on whether your XJ is DIS or not (it should be, but some early 2000 XJ may not have been.) The TJ and WJ got DIS/COP in 1999, while the XJ didn't get it until 2000.

For head swaps, the only change made over the life of the AMC six was going from 7/16" head screws (199/232/early 258) to 1/2" head screws (late 258/242,) so you can drop on pretty much any 4.0L and a good number of 4.2L heads. You can even drop on the earlier heads, if you have the head screw holes bored out to pass the 1/2" screws. (The screw pattern is the same, but the size is different.) Later heads can be installed on earlier blocks using "shoulder screws" (a 1/2" shank with a 7/16" thread, essentially) or by machining out the holes in the block to a 1/2"-13 thread (from their original 7/16"-14.)

HII

DIS = Distributorless Ignition System, right? That's what I've got.

So, with the head cracking problem of the later model motors that I've read so much about here, is it worth having the holes on an earlier head bored out to 1/2? Is there a better or worse head choice if I go with a stroker? 4.0 or 4.2?

Many thanks