MF,
I am fitting short shaft motors to these because I don't have any long shaft ones here at the moment, at least running ones. To get the blade height I have had to press the center of the standard PT oval plate up 20 mm. Bit of a pain but best way out of the problem with these bases. Only other thing I have had to do is drill the 4th hole for the PT motor and move the height adjuster spring to the other side which also required a 3/16 th hole drilled in the base