Going by the deck height and connecting rod length along with half of the stroke, wouldn't the compression height be 1.077"? I looked up Diamond Pistons and didn't find any for this combo. Are they custom made?
I would use a 3.79 type deal with that short deck, but they probably had a bunch of short deck blocks around they need to get rid of.
Yes, that results in a short custom piston. Nothing wrong with it in a race motor