904 slipping

I just double checked the KD and i found a 3/16 of play so i tightened it up. but would that much cause an issue..


Yes, and no
At 55/60 you were probably already in second gear, and the engine was just on top of the torque peak. The engine is putting a hurt on the tranny and the chassis is starting to push wind. It needed all the throttle pressure available, and it still wasn't enough.
Your 904trans will need a lots of up-grades to survive that engine; the least of which is more throttle pressure.