RE: OS engine Parts
Bruce,
There might be a better option, for less dough.
An [link=http://www.hobbyking.com/hobbyking/store/uh_viewitem.asp?idproduct=8988]ASP S.61A[/link] from HobbyKing.
It is an FX clone with a true ABC P+L (unlike OS' ABN/L), so it will last longer.
It is not an under-square engine ('Long Stroke') like the SF was, though.