don't know of a group or source for Corvair conversions

Neither do I, never heard of a Corvair engine in a Vanagon. However, there
is (was) a conversion kit for putting a Corvair engine into a Bay window
bus (Transvair) and I have most of that kit, plus 2 Corvair engines and 2
Powerglide transmissions. Question is, would the adaptors that come in the
kit for the Bay window conversion ( Front transmission mount and CV joints)
work in a Vanagon-don't know, but I'm going to check into it.      Jeff