This engine is regarded as an interference type - that is, if the belt snaps there is a good chance that the pistons have collided with the valves. The only thing to do is to pop a new belt on (about 1 hour) then turn the engine slowly by hand, checking for any interference...if all seems ok then see if she runs - but its best to do a compression check to make sure. If compression is down, then its off with its head, I'm afraid.
John
March 2008