How to clean a block

[Tuna Joe]

Hello all
I recently pulled the engine in my yellow 1968 L89 corvette due to poor compression.
Heads are in the shop being rebuilt and the block has been completely taken apart.
Prior to me buying the car, it sat for a long time and there is a bunch of crude inside the block.

I called up a couple of machine shops and they will put the block in to essentially an engine dishwasher. None have the ability to tumble it with shot (not sure what the machine is called) to clean the water passages and completely clean the inside of the engine.
How are you guys cleaning engines prior to rebuilding?
The block needs no machine work. Mump the engine builder will hone the cylinders, new bearings and rings.

My other question is if I do find someone that has a rotating shot cleaner, will this affect the engine pad stamping?

Thank you