440 Bore size Ford pistons?

Long story short. Valley pan cracked in two places. Water and debris entered engine. Disassembled engine. Machine shop said my bore was .003 too tight.(from original machining done at another shop) Caused a little scoring on pistons and cylinder walls.

Machine shop torque plate honed cylinders to correct bore size, coated piston skirts, polished crank.

The pistons that were in my 440 measured 4.390 That is .070 over bore. Is this a common thing to do? They are Venolia pistons with .990 pins.

With a 4.390 bore, what size bore head gasket should be used.

Many thanks!

I'd start by checking the bore sizes of the commonly available BB head gaskets. Compare that to the 4.390" block bore you have. Not sure how much less you need on the gasket bore dia. That'd be a start

I think the standard Fel Pro PT 8517 or 8519 PT gaskets are either 4.400 or 4.410 Are your heads aluminum or cast iron? if aluminum use the composite type gaskets, if iron look at using the stock type beaded steel head gaskets

Don't forget any chamfer (sp?) at the top of the bore as well.

My first build I used "standard bore size" gaskets. Never checked the overhang into the bore. My fault. Part of the fire ring went away. Not a good day.

Just something to check. I cannot comment for sure, but I've heard some blocks have a larger chamfer than others

codfish

have you sonic checked the block ? What year is the block , I've seen scarey numbers at .040 over ...

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have you sonic checked the block ?

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I was wondering about that myself & it crossed my mind that since it was deck plate honed that you'd think they were savvy enough to sonic check but then there's the problem of them that they missed by bore/honing it .003" too small for the forged pistons