21 stud deck height, gasket thickness, etc. questions.

[frnkeore]

I'm sort of surprised this deck height issue on flat tops hasn't been discussed here before. Seems like everything else has been...

I have explained my use of a 2.139 crank pin and offset grinding, to set the deck clearance, in at least one other thread on this forum.

I've also (in the same thread, I think) talked about the limitation on boring the 21 stud engines, because of the lower center stud location (the reason Ford changed to 24 studs) and that the factory, nominal OD of 3.38 for the cylinder walls.

 

[frnkeore]

A couple of other things that might help, regarding Ford factory specs, is that the nominal, specified deck thickness of the 21 stud block, is .25 and I'm attaching the head bolt pattern for the block. I've added the blue lines to make the pattern clear. Holes that are not at the blue line intersections, aren't head bolt holes
Edit:
All the hole locations are the same as the 24 stud engines, except the lower bolt holes, at are on the center line of the cylinder.

One other thing, while the nominal cylinder wall diameter is 3.38, it is a little thicker, between cylinders at 3.40, specified as a 1.70 from the center line of the cylinder.

Core shift, of course, can effect the actual cylinder thickness.