Putting together a 292, bored to .040 over 312, with a 312 crank. 
Noticed today the pistons are .007" out of the hole.
Hypereutectic pistons, unported G-heads have a mild "street port" done by John Mummert years ago, and will be using a stock B intake. Y-265-S cam from Mummert. Planning to use the "Best Gaskets" head gaskets. Not planning to race the car or rev it excessively high.
Will those gaskets be thick enough compressed to mitigate any problems, or should I cut the pistons down a bit?

Marc, where did you source hyereutectic Y-block pistons? I've never seen them.

If your 312 crank has the stock 3.44 stroke, you shouldn't have a problem with the pistons being .007 out of the hole. The compressed thickness of the Best gaskets is .046; the OEM gaskets are .025. Being .007 out of the hole would give you a quench of .039, which is a good number, assuming those pistons are flat tops. 

Crankshaft turning nut/socket? There doesn't seem to be such an animal for the Y-block. As Ted has said, you can use one for an SBC and have the notch for the Woodruff key enlarged. I made the mistake of buying a socket, which isn't deep enough to engage the Woodruff key. I then bought this: Stef's Crankshaft Turning Nut 41800 ($19.99 from Summit). Rather than taking it to a machine shop, I used a combination of die-grinder burrs and drill bits to enlarge the groove. It was time-consuming and required numerous test fits. I had to enlarge the groove to 5/16ths. The nut will engage the Woodruff key, but not fully with the timing cover installed. Of course, the timing cover will not be a problem when degreeing the cam. 

If you take the nut to a machine shop to have the groove enlarged, take you crankshaft dampener or the correct Woodruff key with you.

Thanks 55. I bought these about 15 years ago from Schumann's when I first started gathering parts for this engine.  A lifter disintegrated on startup back then, and the whole thing sat until last year when I finally decided it was time to rebuild it. I don't see them listed on his website anymore.
They are flat tops. The crank is stock stroke. Looks like I should be good to leave it as is and move on.
Thanks also for the info on the crank tool. I've got the collar for the SBC, and was wondering if there was one available before I have that one opened up. Guess I'm off to the machine shop.

A machine shop should be able to cut the slot on a machine. 

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

MoonShadow, 292 w/McCulloch, 28 Chrysler Roadster, 354 Hemi)
Manchester, New Hampshire