Frank, when I talked to Harry Harden last year, his memory seemed quite fuzzy on some of the "facts" about this motor. While he seemed to have a quick answer to when was it built ("either 1968 or 1969"... I just went with the earlier year), he could not remember what crankshaft he used. So I guess it is possible he could have been in error on the build date. The five head bolts indicate that the cylinders are from a Konig FA motor. When were the first FAs available in this country? The answer to that might help tie down when this "home-brew" was actually created.