A friend of mine has a 1970 23.3 , he tells us it's the race version. It does have some sort of huge drive on the back (clubfoot?) , it's got a flat deck and a low windshield. It's his shop boat and he loves it (personally I think it's the boat he got his first piece of a$$ in ) after a few beers he will say if you look at it in the right light you can see the old race numbers. Well to this day I haven't seen anything !
Two years ago he took a warmed over HP500 in on trade and the old Formula needed a motor so there it went ! The motor made a 27 Fountain run 73 but in the Formula it went 56 on GPS.
Now it just has a 310 in it but it's still fun !