> Note on vacuum advances from the mid-60's: The most > common ones available are set up for the emission > controlled needs from 1965 on - called C.A.P. They > provide nearly double the advance (up to 17.5 degrees) > and if installed will cause your early 60's engine to > ping like crazy. Be sure you are betting the right > one. > Chris, you may be more familiar than I with the early 60 big blocks, but the vacuum advance advances only at part load. Engines typically ping at full load where there is zero vacuum, so the vacuum advance setting has no effect. I think it may be unlikely that an engine without deposits will ping at part throttle if proper octane gas is used. More advance at part load could help gas mileage and reduce coolant temperature a bit by reducing exhaust temperature. D^2