91 Up Exhaust Hedder On 88 4.0

[ckjeep]

i think i may have a cracked exhaust manifold.the manifold for 87-90 is twice as much as the 91 + manifold. i have found some 91s that have flex joints built in.can you use a later manifold on the renix engine?

[cruiser54]

Yes. It will fit.

There is no EGR bung in the replacement. You need a newer style headpipe with a bung for the O2 sensor. 

[91Pioneer]

So what do you do with the EGR "bung" then?

[cruiser54]

Have one welded into the new header. 

[onlyinajeep726]

Or you can block it off on the intake side and get rid of that system.  When I did the newer long block on my XJ, I just removed that system and the Jeep still runs with the Renix controls.

[91Pioneer]

Have one welded into the new header. 

 

I just found cracks in my #5 & #6 ports on my '88 manifold the other day so I'm in the market too. Is the EGR port the same size as the O2 bung? Just wondering because I can't weld it myself, if I pay a shop to do that, it might be cheaper to just buy the one made for 87-90 to begin with. There is one exhaust shop in my town and they are crooks.

 

I'm kind of debating about removing the stock manifold, having it welded, then putting in a flex section in the downpipe (should prevent it from happening again). Also, I know, I'd check the motor mount also.