360 distributor set up

During break in get it fired right away and up to rpm, set timing at 36 and let it run. If you reduce RPM a little, put light on it again and keep it at 34-36 range minimum. Engine has no load on it so running a ton of timing isn't an issue. Think highway driving with vac adv and pulling 45+ timing numbers, more load on the engine there than at break in.

I'd run it in the 16-20 range for initial and 34-36 total once you get it going.

You can do a hillbilly check of the plate for accuracy before ever putting the distributor back together. If you have a degree wheel or a protractor and construction paper. Make a small degree section on construction paper and pop a hole at the center point. Drop this or degree wheel over shaft. Pop the rotor on the shaft with plate installed. Tape a zip tie to extend tip out. Measure how far distributor rotor advance/moves. Multiply by 2, that's a rough idea what the mechanical adv will be.