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post #2 of (permalink) Old 07-03-2001, 08:54 AM
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Re: 4.0L head bolts

Recheck your thread depths in your block, will ya.
I don't recall either syle having staggered head bolt lengths... but my memory could be faulty ...
If you are putting an '84 head on an '80 block, both 4.2s, there is nothing 4.0 to speak about...
For a 4.2L block, both the Hayes and Chilton Manuals recommend 85 ft/lbs or all bolts except #11, which should be torqued at 75 ft/lbs.
The spec for a 4.0L is much higher at 110/100 ft. lbs.
Using the higher torque spec of a 4.0L on a 4.2L block can cause cylinder wall distortion on torque down ... a bad thing so don't fudge it.
The only best way to use the 110/100 spec on a 4.2L block is to have a torque plate (you can rent one from Clifford) bolted to the deck at that spec during cylinder wall boring which negates cyl wall distortion.

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