1994 mighty max tranny rebuild r5m21

i am looking for a rebuild kit with synchros for a 1994 r5m21. i keep finding kits for the km132-8 , km131, km 132. are these transmissions the same? i thought these were narrow blocks and the input shaft bearings are smaller? looking for a kit to use for later.

thanks

Bump, I am also curious as to rebuild kits for the r5m21! Can't find much on these transmissions. I assume there is very little differences between the KM series transmissions.