Mag
The base 10-51360(without the dash number) fits Continental C85 thru C90 and Lycoming 0 235 thru 0 360.
Referring to the Bendix parts list the only difference for the two digit dash number appears to be the lag angle of the impulse. The -26 is for the four cylinder Continental.
Spruce only gives a partial listing of impulse lag angles. The larger the engine and the higher the compression the greater the lag angle. 0 320 is 25 degree lag, 0 360 is 35 on the Spruce list.
What engine do you have and is the compression stock or modified? The impulse couplings were $400 plus a couple of years ago, probably a lot more now.
I don't know if its practical to change the lag angle of the impulse coupling. I'm not sure what lag angle I have on my 0 320 with 10-1 pistons. It works perfect, starts on the second blade, never any kickback. Kickback would be the main concern on 0 360.