Small Engines (Lawn Mowers, etc.): B&S on a Craftsman, head gasket, clearences

Question
Have a 2004 Craftsman rider with a B&S Intek 31O777 0036 E1 model engine. Have replaced head gasket twice. Now the thing blew and the connector rod went through the block housing. I want to replace with a different engine and wanted to see which Kohler model would be interchangeable. Or any suggestions on something that may be better.

Answer
Buy a new tractor!   A replacement engine will be more than this mower is worth.  You are stuck on this one Jim.  When a tractor is built it is built around the engine.  Virtually nothing will hook up the same and the clearences between body panels will be iffy.  We haven't even started talking about how to find a muffler that fits.