[Bluesman]

I will give you a simple example:
My engine's total advance is 36 degrees at 2500 rpm.
I set the timing light knob at 36 and rotate the "just finger tight" distributor until the strobe shows exactly 0 degrees on the harmonic ballancer (crankshaft dampner). That is the big white chalk mark at zero. Don't forget to tighten the distributor when you are done. Good Luck!