With the engine at normal operating temperature, advance the timing until it just begins to spark knock on a hard acceleration. Then retard the timing, one or two degrees at a time, until the knock is no longer there. This is exactly what the knock sensor does on computer controlled engines, (advances the timing as far as possible without spark knock).


Keep in mind that after you get ignition timing adjusted, if you use fuel with a different octane rating, the timing will need to be adjusted accordingly. Higher octane=more advance, lower octane=less advance.

 

With the holly carb on the Edelbrock performer the
th350 vacuum modulator line that normally is hooked into the intake is blocked…can the vacuum modulator be hooked to a vacuums port on the carb? Also there is no were to hook the brake boost to? I was thinking of Ting it off the PCV but that seems like a poor solution. As always any help appreciated

 

The modulator and brake booster must both have manifold vacuum, (below the throttle plates). If there are no other vacuum ports on the Edlebrock, your only option is to "T" it off the PCV.