My buddy kept asking for one when we rebuit a Buck V8 recently. Engine ran great, all you could ask for.
Set points to .016" gap on the GM V8 points type dist.
If the dist cam " bumps" dont show signs of wear ( rounded off) you are good to go with just setting point gap.
I only really needed my meter to indicate that the dist cam is shot. example for GM V8
if .016" gap doesn't return 30 deg dwell +/- 2 - it's time to get a new dist.
if the car is lazy with the right gap then the dist is likely worn ( all else working ).
Remember to use the correct ballast resistor or the resistance wire the ignition is designed for.
OTW you will be toasting points weekly
the full 12 -14V batt at the coil should only be there for starting - not for engine RUN.
- Ken NIASE Master from the way, way Past-er