T67 !!!!
Chev methinks the SAH1 with a simple 0320 and fixed pitched prop would have been the way ahead.
An 0 360 option could also have been considered.
The Bulldog was always an expensive (heavy) answer to a simple problem, and the T67 (German design) had issues to the point that the Americans cut up their fleet after service rather than release it to civilian use.
Whilst all this is going on the dear old C172 (decades old) is still training pilots all over the world.
The SAH1 was a 'Pup' without the complexities and expensive doors . It was designed from the outset for simple mass production but retaining the good handling qualities. The Bulldog was just an ongoing (heavy) Pup with no real improvements, other than a canopy.