So your engine number is 7613100, with no letter prefix at all?
That sounds like a 1200cc 40-bhp engine, which would have been the original engine fitted to an Australian 1965 Beetle. For US (German) cars the number dates to around March 1963, but Australian-built cars don't match the US/German dates and are usually a few months behind.
When you mention the 'Sydney' site do you mean this one?
http://www.clubvw.org.au/vwengines
It only says that early VW engines did not have a letter code, and were only consecutive numbers. No listing of any air-cooledc 2.2 litre engine, as there's no such thing. (as standard, anyway).
