If you decide to swap to a 235 engine, the same "no leak" seal modification can be done to it. I'd suggest finding a rebuildable 235, preferably a 1954 or early 55 production engine with the water pump in the same location as a 216, and rebuild and improve it, it instead of risking a disaster with the 216 if some old geezer like me doesn't build it. I was among the last bunch of professional mechanics who grew up working on Babbit rod engines, back in the late 1950's.
Jerry
