As the lead in says how much HP can one get out of a VW 4cyl engine set up for an airplane? I know much of it depend's upon overall displacement but whats the upper end one can get? I've read that 80 HP was the top end but also have seen 85 and even 100 HP advertised? I know I'm still learning but I'd really tought that about 72 HP was the upper limit. What gives here? Is it the use of redrives or some truly custom machine work beyond the skill level of an average person? Will someone please clue me in because I really like the VW engine but I thought if you were looking for 80-100 HP you had to consider the CorVair engine, which I also like. Thanks, wasn't trying to rant, just confused.