4.0 Head on a 4.2 - JeepForum.com
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post #1 of 3 Old 05-04-2021, 06:45 AM Thread Starter
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1985 CJ7 
Join Date: Mar 2021
Location: Kinston
Posts: 20
4.0 Head on a 4.2

I know I'm beating a dead horse.

I've read the post on here and other places and the more I read, the deeper down the rabbit hole I go.

I have a 4.0L head (0630 Casting) I want to put on my 4.2L. My current setup has HEDMAN long tube dual port headers, Offy aluminum intake, Edelbrock 500 carb.

I know I'll have to block off some of the water ports in the head.

Should the (4.2) push rods be the correct length?
Will the headers and intake match up?
do I need 4.2L or 4.0L head gasket, and intake/exhaust gaskets?

What other surprises should I expect?

85Tuxedocj7 is offline  
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post #2 of 3 Old 05-06-2021, 09:22 AM
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1993 XJ Cherokee 
Join Date: Mar 2018
Location: Savannah
Posts: 90
I've read about this before, but never done it myself. Isn't the purpose of using a 4.0 head on a 4.2 so you can use the 4.0 HO fuel injection system to upgrade from the carb? If so, you would be using the 4.0 intake manifold. I don't know about the header, but you may need to see if that header will fit a 4.0 and use the 4.0 gaskets.
BaileyNB is offline  
post #3 of 3 Old 05-06-2021, 01:51 PM Thread Starter
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1985 CJ7 
Join Date: Mar 2021
Location: Kinston
Posts: 20
I don't plan to go FI.
85Tuxedocj7 is offline  

4.0 head

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