Argh...It sounds like you got the advice you need so far, you'll probably want to start with the valve covers off, plugs out and turn the engine by hand looking for the obvious. If the plugs or pistons as seen through the spark plug holes don't have obvious problems and it turns freely you could use a compression gage and look for odd cylinders. It's good to be an optomist but hard sometimes. You could always hope that you merely blew a head gasket, water seeped into the cylinder before you tried to start it but didn't actually damage parts, just prevented the engine from turning. If you need any help or tools just let me know.
BTW, throwing belts or blowing
oil by themselves might not mean anything. Cars like this often wind up with pulleys that don't line up well and can throw belts. If these were some of the first times of heavy throttle you could have had blowby from still fresh rings that could cause
oil to come out of breathers, either one of those problems could be unrelated and possibly unimportant.