Winterizing a 97 Scarab Sprint, jet drive

[joecal]

Hello, I need to winterize my boat within the next month or so, that has a transplanted 350ci (originally it had a 4.3) and the original Volvo/Penta jet drive. I've watched several videos on YouTube but am still a little confused. I've always had I/O's so this is a little different I'm guessing. I never used anti-freeze before and never had a problem in the spring, well once I did but that was my fault. I don't see any petcocks on the original exhaust manifolds taken off the 4.3, so I'm assuming to pull off the hoses at the front to drain them? The block has one drain on each side, so that's not a problem. I guess too pulling the hose off the bottom of the water pump would be a good idea. Is using anti-freeze really necessary? I know I need to fog the motor and use Sta-Bil, and I'm going to change the oil and filter. It does get pretty cold here in the winter, and I don't want any surprises in the spring if I can help it. I notice some people drain the block and manifolds before using ant-freeze which to me didn't make much sense. Running the engine on anti-freeze would flush out any water that's in there I would think. Once you start seeing the ant-freeze coming out the exhaust. Maybe I'm missing something. Any help is appreciated.