Hi Kafur 1
Well spotted it is a type 1 with a standard type 1 oil cooler layed down. there is a guy very close to me who builds aero engines from vw type 1's and this is a mod that he uses he has designed it himself and also he has made a lot of other things for his engines including his own fuel injection system, oil system for inverted flight etc , he has now retired and only does it for a hobby , it seems to work well for me,, so far on the little use i have had of the engine when it was in the car.I am also running an external cooler.
Here is a pic of it :=