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Rreplace the siezed 258

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Discussion Starter · #1 ·
I have a 1980 j10 258 4 sp

My 258 in my 80 j10 has seized. I have not torn into it see what was the cause yet and how messed up things are in. I do have a 4.0 from a early 90's Cherokee sitting in my shop that I could possible put into it.

My head from the 258 is good. just had it cleaned up and new seals put on the valves and I could reuse it.

What headaches am I going to encounter by attempting to do this?

I do have exhaust manifold from the 4.0 laying around that I could use.

so I think I will be looking at using a 4.0 flywheel and clucth. but I am wondering if the bell housing will bolt to 4.0 and the motor mounts will work.

Suggestions and recommendations would be helpful here. I know it is "JUST" 10 years difference in engines. but I am sure there is a difference that will need to be addresses.

Any other recommendations would be helpful

Thanks.
 

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Swap the entire 4.0 in, leave the head on it and keep the EFI. There's lots of info on the web on 4.0 swaps. Most of it is CJ related, but there's nothing CJ specific that won't be applicable to your J10.

The bellhousing pattern is the same as are the motor mount lugs on the block. One bolt hole will require a metric bolt, not sure why they did this.
 

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As CSP said.
I would post in the CJ forum. Quite a bit of information on 4.0 swaps up there.
 

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It will bolt straight in.

The ancillaries are different of course and you would be better off with the 4.0 head which flows better, and the fuel injection.
 
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