Thank you all for the replies.

It is about a 15 to 20 foot boat similar to a ski style boat. No cabin or fishing rigging. Sorry I am not that much on the correct boat jargon. No idea how he uses it. A guy was trying to sell him a short block with rust in the cylinders for $1500 when I said no let's look at other choices.

I will definitely look at a crate motor.

The heads were reworked about a season before the cracked block was found.

It had a crack in the block and one exhaust manifold but aside from that the boat specific parts are ok.