Hybred Help Needed

So... we have this hybred street rod... a 1930 Model A Pickup. Might be an 80's vintage Mustang column & switch - going to a GM 4.3 V6 (not Vortec). It has gradually become almost impossible to start - suspect no power to the coil in Start mode. No fire at plugs while spinning over. If it does start (once out of 100 tries), it runs smoothly. Has an old DelcoRemy dist/coil. How to check if no power from the ignition, since I don't know which wire/terminal to look at. Help, please!

Got 12v to the plus side of coil whenm cranking, or 6v to the coil key on? I assume it has points? Do you know how to do basic ignition tests?