Ayuh,..... Welcome Aboard,....... The Alpha drive has a raw water pump in it to supply the water,....
The water pump on the front of the motor is just a circulator pump,.....
Ayuh,..... Welcome Aboard,....... Not much different,......
Year of production,....
2bbl. or 4bbl. carb,.....
3" or 4" heat exchanger,......
The basic motors are all the same, 'n generally leave alot to be desired,.....
Ayuh,..... Welcome Aboard,......
As noted, the old parts are scrap,.....
That hole in the block used to be an air bleed hole, so the block would fill with antifreeze in an automotive app,.....
It was deleted years ago,..... ya don't need it,.....
Ayuh,..... This is why I always just hang the motor, attached on the transom, align the gimbel/ coupler, 'n measure where I have to build the motor mounts out to from the hull,.....