What donor engine for a 4.6 stroker build?

  • 1991 to 1995 Wrangler YJ and 1997-1999 Wrangler TJ 4.0 blocks will interchange in XJ / ZJ and vice versa.

Anyway, I'd stick with one from the vehicles mentioned above. Good luck and be sure to start a build thread!

OK now I am confused - why would I be looking for something that interchanges with an XJ or ZJ? Its an '02 TJ block into a '99 TJ that I was asking about...
 
OK now I am confused - why would I be looking for something that interchanges with an XJ or ZJ? Its an '02 TJ block into a '99 TJ that I was asking about...

Because you are looking for a block for a 99 TJ. These are the blocks that will easily transplant into your rig. It says "vice versa" so the XJ/ZJ fit the TJ.:

  • 1991 to 1995 Wrangler YJ and 1997-1999 Wrangler TJ 4.0 blocks will interchange in XJ / ZJ and vice versa.
This is why:

TJ / WJ 4.0 engine blocks underwent clean sheet design changes effective in the 1999 WJ Grand Cherokee and 2000 TJ Wrangler. These blocks are not interchangeable with XJ / ZJ engine blocks. The reason is due to the motor mount bolt holes and belt driven accessory mounting bolt holes being in different locations, or not present at all (TJ / WJ vs. XJ / ZJ).

Otherwise you will have to modify stuff and make more work for yourself than is necessary. I hope I'm making sense as I've only had my first cup of coffee.

Edited to add:

The next post in that thread is below. I don't know if the 99 is a different, one off animal or not:

Jeep 4.0 Engine (1996-1998)

Fits the following vehicles:


1996-1998 Jeep Cherokee 4.0 Auto or Manual
1996-1998 Jeep Grand Cherokee 4.0 Auto or Manual
1997-1998 Jeep TJ Wrangler 4.0 Auto or Manual

This is due to holes for mounting accessories. A/C location is a big one.
 
OK now I am confused - why would I be looking for something that interchanges with an XJ or ZJ? Its an '02 TJ block into a '99 TJ that I was asking about...

You can only use an 02 tj block if your current motor doesn't have a distributor and has two exhaust manifolds,coil bolted to the head over the plugs and a tensioner arm on the belt

Its either early or late block. He gave a source for early blocks.

You want a yes or no answer and be done. Unfortunately you will actually need to pop your hood and use your brain to be sure what you have.it is probably an early block,but YOU need to verify it.

All the info you need is already here in this thread. Sorry there are also some wrong posts saying you'll be fine with a late style block even though they don't tell you to check first.
 
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I'm interested in this. My '04 still seams pretty strong after 300K miles, but it won't last forever. Thinking about sourcing a block to build a stroker so it's ready when when my origininal 4.0 goes kaput. Is everything available to build a stroker on an '04 4.0 doner?
 
I found a '99 donor engine! Resolves any lingering concerns about interchangeability of accessories or ECU compatibility issues. The donor has had a hard life and the main bearings look pretty worn but as a donor it should be fine once it goes through the machine shop, gets rebored and gets all new internals.