I have a FRPP steel timing set. The crank key only fills up about 1/3 of the groove in the lower timing sprocket. Width wise it fits well but it isn't very tall. The groove in the sprocket is just so much deeper than stock and the balancer, the key doesn't fully fill those either. Are there aftermarket crank keys out there that are taller than stock? I goin to my machinist tomorrow to see what he thinks (hardcore ford guy) and replace a ring my dad busted.