Amerkin

This is often referred to as the out of the hole measurement. Can anyone help me out?

Blackonblacksls

This isn't something that is the same from one block to the next.

Seen factory blocks with pistons in the hole even.

LT5 John

from the service manual. Cylinder head deck height-measuring from the center line of the crankshaft to the deck face- 9.235-9.245 in


exactly!
watch this vid below

HOXXOH

Using calipers to measure depth when the expected dimension is small is the wrong tool for the job. Use a depth micrometer if you want accuracy. To find out piston movement in the bore, move the dial indicator to the edge of the piston that is perpendicular to the wrist pin and rock the piston. For greater accuracy, use a tenth indicator instead of a 0-1"

LT5 John

I agree. the video was just for a reference, how some check...The OP wanted to know what GM uses as spec...which I indicated based from the service manual docs...

JMB

Mine measured out at 0.005" out

Michael_D

Should be plus five. It's always good practice to check all four corners before pulling the rods out. Then you know if you might need to hone the mains or re deck the block, or both to square it.