I have had no issues using the four longer bolts at the top end holes in the heads on the ’54-55 Y engines.  As Charlie and the Ford Bulletin mentions, thread retention on those four particular holes (two per side) is improved when using the longer bolts.  When using the ARP head bolts, I will install the bolts first without the washers to ensure that the bolts do fully seat against the bolt heads before removing to install the washers and then torquing the bolts.  When milling the heads and blocks, the head bolt thread lengths do get dicey.

Lorena, Texas (South of Waco)

So of what Charlie posted, the dowels were moved further into the block (machining protocols - both early and late used the same dowels according to the MPC), for whatever reason and the added depth required longer bolts at the dowel locations?

This change came on the first run 1956 production? Wonder if FORD had gasket sealing problem(s) on the 54 and 55 block?

Learn something new everyday.

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No, I don't think the position of the dowels changed.  It is simply that the reduced thread engagement caused by the counterbore caused issues, which a longer bolt fixed.



Lawrenceville, GA

No, I don't think the position of the dowels changed.  It is simply that the reduced thread engagement caused by the counterbore caused issues, which a longer bolt fixed.

Now that makes sense. Reduced bore thread as a result of the dowel insertion.


THANX!

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