The big decision is made irrevocably - I've bought an engine. The engine was built in 1970 and is a Lycoming O-235-C2C originally out of a Grumman AA1 Yankee. Subsequently, it was installed in a pusher configuration Rutan Long-ez, hence the forwards facing exhaust pipes. Unfortunately both of these aircraft were written off - in neither case was the engine the problem, but hopefully it's third time lucky. The engine is first run and total time is only 820hours since new. I need to establish whether in the Long-ez accident the engine suffered a prop strike and needs a shock load inspection. In any event, the runout on the flange is not measurable and the prop was wood so hopefully there won't be any internal damage although the price paid allows for repair if necessary. The engine is rated at 115hp for upto five minutes and 108hp continuously. The C2C version of the O-235 is an interesting engine. It has the same cylinders and crankcase as the original O-235-C used in aircraft such as the Piper Colt, but has the same crankshaft as the current O-235-L2C and N2C. The crankcase has a conical engine mount which makes the engine mount easy to fabricate and uses much cheaper mount rubbers than the dynafocal mount engines. Now that I've got an engine I can order the tubing to fabricate the engine mount. 
