Yes the old dizzy spinners, they are cool thing to se . It's a great way to see how your could work too, the lack of time in the rpms to dwell can really show how little spark there is this way. The last few years I've really come a fan of locked out dist, but it needs some form of cranking retard or power interrupt while cranking to get the motor moving. My favorite has been the 6520 box from msd. They have a add on box part number 8987 that dies cranking retard and will give a top end or nitrous timing pull out. I have never tried it, but feel if you already have a box its would be worth the try and cheaper than a new all in 1 box
Make sure the fuel line is thoroughly insulated between the fuel pump and the tank, especially near any part of the exhaust. Coming from the pump to the carb, keep the line away from hot spots such as radiator hose, thermostat housing or intake manifold. The potential for disaster is just as critical as timing problems, and often the last place to be checked.
The MSD 6520 is the Digital 6 ignition. That is the box I have been using for years. It has a 20* crank retard that can turned off and on with the cylinder select rotary dial, no add on box needed. To use the high speed retard requires add on components. There is a pink wire in the box harness. When that wire receives 12 volts, it retards the timing by the amount selected with a rotary dial on the side of the box. I wired mine using an MSD 8950 (RPM activated switch), an MSD 8670 module selector, and a relay. The RPM switch grounds the relay which sends 12 volts to the pink wire. The module selector allows me to select the RPM (3000-5200) that closes the switch.
