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89 4.2 w/ 4.0 head

Posted: June 17th, 2021, 1:54 pm
by Shrek
Prior to any knowledge of stroking a 4.0, I had a 4.2 at the machine shop and I am putting it together. I have the old 4.2, It has very little to no compression on the #1 cylinder and #2 is following its lead. I was running a Howell California TBI system which was way better than the original carb with emissions equipment.
This is what I have for my build so far:
89 4.2 block bored .040 over
Comp Cams 68-301-5
Comp cam lifters 822-12
Comp Cams timing gears and chain.
96 XJ Header
99 intake and throttle body
95 wiring harness
95 ECU

When I upgraded to an external slave cylinder, I installed a new clutch and replaced the fly wheel so I could use a CPS.
I followed Jeep-Power's build thread and have found it very useful. Thank you.

I do have questions of course.

I had a "V" belt system, but would like to go to serpentine. Can I use my 4.2's alternator bracket but use an alternator that has a higher output?
Can I use the power steering pump with reservoir and mounting bracket from an XJ?
Can I use the Summit Racing 850047 HEI distributor? How does it connect to the ECU if at all? Or is it better to go with the stock distributor and coil? Is there an upgrade for the stock coil?
I would like to put the fuel pump in the gas tank, suggestions for a high flow pump? Injectors to go with it?


I am sure there will be many more questions. I will start posting pics ASAP

Re: 89 4.2 w/ 4.0 head

Posted: June 20th, 2021, 6:02 am
by Shrek
I had some time to start preparing for the swap. I removed the grill/radiator, pulled the motor, removed the wiring harness ECU, as well as the throttle cable and linkage.

IMG_4734.jpg