On another board I heard a member state that the flat four engine found in Subarus have the same bolt pattern as the flat four in a Bug…one could theoretically do a direct engine swap.
A VW/Porsche swap I could see, but a Subaru?
Well, I don’t know whether the mounting story is true, but the lack of plumbing for a water-cooling system in the bug would be somewhat of a handicap. Guess one could mount a radiator on the roof or something.
Apparently it can be done, but it requires an adapter plate, adding a cooling system, and so on. The link below is actually for a Vanagon page, but it should have any info you need: