i went to check the total timing and i got a weird problem on this new car I bought. Its a 65 fastback with a 87 302HO roller motor. it has a msd distributor with mech advance, msd 6a, and a msd coil with taylor plug wires. When I start to rev the motor the timing will start to bounce around between 30 and 40 like crazy making it impossible to actually set the timing with the #1 plug wire. What would cause something like this? Everything on the motor seems new with very little use.