• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

96 4.0 manifolds on 01 head

Overland

NAXJA Forum User
There doesn't seem to be much discussion in regards to using earlier manifolds on newer heads because I suppose most people go the other way. I just picked up a rebuilt 01 engine which runs beautifully for dirt cheap, but I need it in a 96.

Should the ports on my HO manifolds be the same as the 01? Can I use the newer intake with the older exhaust manifold?

Should I just swap the older head onto the newer engine?
 
I would put the older head on the newer engine simply because it's a better head design.

you should have an 0630 head on your old motor, it's one of the better units.

most of us are replacing 0331 heads with older ones because they don't suck.
 
The exhaust ports on the 01 (0331) head are smaller and more square in shape than the older style heads. When going from older to newer an adapter is needed to make them fit right.

In your case when going from newer to older, you can run the older style header and gasket. Since the ports on the 0331 head are smaller it wont effect anything as they will just dump into the larger manifold.

So yes, you can keep the newer style intake, and use your older style exhaust.

More info here:
https://jeepexhaustadapter.com/exhaust-port-sketch/
 
That illustration tells me what I need to know.

I assume that since the engine was rebuilt, the head should have been addressed. It has the brown film typical of a neglected cooling system but not the major sludge accumulation I've come to expect. They said it's been two years, looks about right I guess.

If I can bolt my original manifolds to the newer head, I can swap with less work for now. I'd also rather leave the head on the old engine when I put it in a crate so it'll keep better. Really, all it needs is cam bearings.

I wouldn't mind running the new intake as it's regarded as an upgrade, but I expect I'd have to change the exhaust to swap headers. I have time and money in the exhaust and it's as good as it gets already, would rather just keep it.
 
Back
Top