Hey Crash,
SPUD here-I have the 91 OS 4C in mine with the stock mount & have had no problems. I originally had a 70 4C on there but went to the 91 with no problem. Same mount just had to drill two holes in the mount for the dif motor, not the fire wall. I grind the round nose wheel bosses off of the mount for clearance if the mount has them.............Hope this helps.

SPUDs out.................see ya.