It should have 4 motor mount bolts, 1 on each corner NOT including that torque stop.
There is one that is hiding under the jack-shaft bracket that angles up into the rear PTO corner of the engine. Check that as well.
This would def cause a issue with RPM among other things. Was that torque stop just loose or any of the other bolts?
Next thing would be to check Center to Center and offset while you are re bolting the motor in.
1993 Wildcat 700 EFI- river runner
2000 ZRT chassis/Wildcat 700 EFI motor swap. Stock