I have a 1990 YJ with the enimic 2.5l. I've been reading about the 4.0 TB upgrade and what I can tell is that if you have the 4 bolt intake then you can upgrade, if you have the 3 bolt intake then you can't.
Here's the skinny, I just looked at mine and it looks like it has 4 bolts but they are not symetrical spacing. They don't look like the hole will line up on the 4.0 TB's that i've seen for sale.
o o 0 0
0 0 0 0
My TB pattern 4.0 TB pattern
Any ideas if I would be able to make the swap???