90laredoo

I've been doing some research on doing a head swap on my jeep and I read somewhere (can't remember where) that the 91-96 4.0L's heads had better flow rates compared to the pre 91 4.0L head.

Sooo... long story short I've been looking into swapping mine out for a 91 and newer head and been looking to see what's different about them and can only find that the intake and exhaust ports are different. Thus, requiring the manifolds that the head came with.

So my question is, is there anything else I should know before I go for the gold and swap these puppies out? I'm pretty sure they're gonna be the same as far as coolant passages and oil galleries go but I just want to make sure before I get in over my head on this.

Any input is appreciated Thanks!

And any info on where I can get stroker parts would be amazing


Idk if this is the right place for this thread so sorry if I got it wrong :/

classicherokee98

505 performance for stroker parts or hesco performance they have really good stuff as far as the head goes i'm trying to figure out the best head my self

Donnie_K

you can match the flow or beat it by porting and polishing your current head.

91XJMudMan

I put an 01-06 head on my 96 and it bolted right on. I ported and polished it before i installed, and port matched my intake manifold also. I definitely gained more flow. the throttle response is more significant, and it revs up much faster than i thought it would.
If you get a newer head, switching to the newer H.O. manifold isnt needed. It can be done but you will most likely need to switch over to an OBD I or II H.O. ECU sytyem so the throttle body and all the sensors work right.
If I were you I would stick with the non H.O. intake manifold and OBD I system to keep it simple, but if a new head is needed, go get an 01-06 head and do the port/polish and port matching of the intake

Donnie_K

actually... the HO throttle bodies can be adapted over to renix pretty easy. But I think his 91 is HO anyway.

91XJMudMan

well his username is 90Laredo and his profile says he has a 90... So I assume he owns a 1990 Laredo lol