if your thermostat is stuck open, the motor will never get to operating temperature to burn of condensation.
change the oil a few times, fix the thermostat issue and then take the boat for a good run at temperature.
no, I think its coming from a busted block. the core plugs on the 229 are on the back of the block and on the front of the block. I do not recall core plugs on the sides of the block
I have used the pour and spread method. pour resin on the cloth, spread with a 12" bondo spreader. for two layers of 3/4, you may have to back off on the MEKP just a bit to slow the kick to work fast enough.
in addition to old poly belts, old leather belts from your pants work in a pinch
I have used needle nose vice grips and my belt on more than one occasion