59A flathead timing

[quickchangeV8]

Hi all. I have a 59A flathead engine in a 1929 coupe 276 cu in Eddie Meyer intake with dual Stromberg 97's Sharp heads and using an Isky 400 Jr cam. Using the front mounted distributer with Pertronix conversion. I suspect the timing is off somewhat. The car runs OK but if the car sits for a while there is a slight backfiring out the exhaust until the engine warms up and there is a gasoline smell as well inside the cab. Which way do you turn the distributer to get rid of the backfiring and by how much? If you are standing in front of the car which way does the distributer get tuned? Thanks.