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Old 08-09-2013, 11:28 AM   #1
1987Wrangler YJ's Avatar
Join Date: Jun 2013
Posts: 567
4.0 head on 4.2 block.

Sup yall. I have been wanting to do this for some time now. I finally got my weber carb and want to start gathering parts. Can I use my stock intake/ manifolds? will the thermostat cover fit on the new head? can I use either a 4.0/4.2 head gasket? is doing all this even worth it?

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Old 08-09-2013, 02:19 PM   #2
Join Date: Apr 2012
Posts: 840
heres a thread that explains it. personally I wouldn't do it unless I was going all the way with FI but a lot of people do it and like it. I believe you can improve on the 4.2 head by cleaning up the casting in the ports, port matching it and shaving 10tho off it to up compression.

Jeep Strokers • 4.0 head and EFI on a 4.2

and here

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Old 08-09-2013, 10:10 PM   #3
1987Wrangler YJ's Avatar
Join Date: Jun 2013
Posts: 567
My truck has the retarded plastic valve cover. I was hoping to ditch that. would getting the 88-90 head with the alloy one, then getting that rebuilt be a good idea? my jeep only has 50k miles. I still want to get a head redone for some better hp and compression
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Old 08-10-2013, 05:55 AM   #4
Join Date: Apr 2012
Posts: 840
from what I've read your head can be drilled and tapped for the alum. valve cover.
or you can pick up a used one, get it ready and save down time. when you have a machine shop do the valves have them shave 10 thousands off the deck.
look into the ports, you will see a casting ridge that should be removed with a die grinder, then port match it to the intake manifold. there are videos on youtube that show how to do it.
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