Technical Mini-starter wiring question?

I wired up HEI in '65 GTO, the factory switch did not provide 12 volts to coil in start position just as described above. I had to use the R terminal to get it to start. I later changed to a newer switch and removed the R terminal wire from the system. Splicing start and run together made the starter keep running, I didn't have diodes big enough to use at the time or the knowledge to know where to install it.