Mopar efi v belt harmonic balancer on a 4.2 long snout crank will it fit a 1991 4.0

Swaping 258 to 4.0, 4.0 parts to 258 etc!
BillyC
Posts: 3
Joined: March 1st, 2022, 1:45 pm
Vehicle Year: 1988
Vehicle Make: Jeep
Vehicle Model: Yj

Mopar efi v belt harmonic balancer on a 4.2 long snout crank will it fit a 1991 4.0

Post by BillyC »

I have a 1988 jeep yj 4.2L that I have installed a 4.0 head and mopar efi setup on using the v belt front trigger harmonic balancer. The engine is long past needing reworked. The block is a wide block with 1/2 inch head bolts. I used a Detroit red gasket and did not seal off any of the cooling ports in the head but have not had any coolant leaks. I have 2 stroker kits with long snout cranks but I sold one of the Jeeps in the cash for clunker deal and lost my 4.0 block I had for my swap due to the person in possession of the block passing away. My jeep is stored in Southern KY, so I was looking to do a quick swap. Would a 4.0 short block work with the short snout crankshaft and v belt Setup? I would like to keep my v belt 1 wire alternater and Saginaw power steering pump.
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IH 392
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Re: Mopar efi v belt harmonic balancer on a 4.2 long snout crank will it fit a 1991 4.0

Post by IH 392 »

I don't see why it wouldn't work?, make sure the bolt is torqued with a good slobber of red LocTite.
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