My car ('70 mustang 302) has been pinging for several weeks. I have tried putting in every single spring combination in the msd distributor but it doesn't seem to make much difference. The timing is at 6 degrees and the only way i can run the car without pinging is if i eliminate the hose (vacuum line?) that runs from the distributor to the carb. Would running the car without the vacuum advance cause any sort of damage?