A friend of mine has a 1992 cone clutch King Cobra that is "popping" out of gear once in awhile. It seems to be mainly when he is getting on plane and there is more load on the drive.

Once it "pops" out if he takes the shifter to nuetral then back into gear it will be fine. No grinding or any other noises at all.

check shift adj. and make sure he is using synthetic drive oil.

We have checked the shift cable and checked the shift mechanism on the drive for proper play. He is running Merc Hi-perf gear lube.