What Engine can I use to replace my Kawasaki fh661v on Cub Cadet RZT 50?

I was getting the mower started after a rough winter here in the Mid West. Got my Cub Cadet RZT 50 started after checking the oil and charging the battery. Started up fine took it for a ride around the yard powered it down to park it . And it sounded like I ran over some chains with my blades on. Something came loose in the engine and knocked a hole right in the block by the filter. So I am interested in knowing what engines can I replace the Kawasaki with and still hook right up to the electrical plugs and bolt pattern? Help me please.