'91 header on '88 block

[Jeepin_FF36]

i was wondering if i would be able to bolt a header for a 91 4.0 engine to my 88 engine

[slvmart]

Are you talking about the factory exhaust manifold ? Or a aftermarket header ? Exhaust manifolds have different lengths, so likely the pipe from the manifold, back, will be different. Forget if Renix was shorter, but I think the Chrysler OBD2 design is longer.

[Jeepin_FF36]

Aftermarket header

[Jeepin_FF36]

im taking it with the lack of answers its a no or something im going to have to find out in my own

[4.3LXJ]

It going to be tough to answer that question about aftermarket stuff. The best thing to do is contact the manufacturer on that one

[Brasscatz]

There are slight differences in the 4.0 over the years and I don't have much experience with any of them older than '97. Now, the differences are subtle in most cases, but I honestly couldn't tell you about header fitment between years like that. I can tell you that I had issues with the stock exhaust manifold from my original 350 in my old pickup when I replaced the motor with a newer model 350. The bolt holes didn't line up correctly but I was able to make it work. You might run into the same issues with your situation.

[Rocco83]

Brass is right about subtle differences over the years in 4.0L. The engine I just pulled is a 98, the engine I'm replacing it with is an early 90s that was remanned in 04 and there are enough slight differences that I have to use many of the old parts as they aren't quite close enough to use the new parts. The header is one of the parts that don't go from one to the other. Those are OEM.