Valve cover differences

Ok, so my buddies 91 4.0 has a cracked valve cover. The head and all is a whole separate matter that we are working on, it over heated and etc. Anyway, I am looking on teamcherokee.com and I see that there are different valve covers for different year eras. I can deffinately tell the difference between my 91 valve cover and my buddies 00 valve cover, however the one for 94 - 96 era...can that not just bolt onto our 91? The difference I see is the placement of the pcv holes, but does that have a real affect? Or even still, can I get one off an OBDII model?

Don't take my word alone on this but I believe the H.O. valve covers are the same bolt pattern. I think it's on MadXj that some one swapped a Newer style onto an older head for the different hoses. Bigger hoses and it had something to do with reducing blow by. The best way to figure out if it will work is take a trip to your local you pull it and take off a few Vcovers and swap them around on a jeep there thats your year.

The newer ones will help reduce blow by, and the only thing that you will have to work with is the gaskets are a little different iirc

I'll confirm the bolt pattern is the same, and it does reduce blowby.......I'm running a 98 stamped steel VC on my 87 4.0. The gasket is different and you have to route the CCV hoses a bit differently, but it works like a charm. It doesn't insulate the valvetrain noise as well as the older covers though, but nothing on my MJ is quiet anyway
Jeff