MK-IV had redesigned Vagabond style cowling, front mounted radiators, fiberglass wing tanks, Matco hydraulic disk brakes and wheels, Maule tailwheel with 11/2" tailspring, offset was taken out of fin, offset front mounting taken out of stabilizer! Steel tubing dorsal, belly, and side stringers. External Baggage Locker. Ser #’s 900D to around 1550D.
Here is a link to Avid Specs