Well if your truck is equipped requiring the R terminal you could use that diode kit. That may apply if you have a points distributor. You don't need to attach a wire at the R terminal if you have an HEI distributor that has been wired with a regular wire instead of the resistor wire that was going to the external coil back when your truck had a points distributor. Or you don't need to attach a wire at the R terminal if you have a points distributor with a coil that has been wired with a regular wire instead of the resistor wire because you have changed your coil to one that runs on the full 12V such as the one dmb mentioned in this other thread.
https://67-72chevytrucks.com/vboard/...83#post9285783
So, do you use the R terminal, or do you need to use the R terminal on that new engine?
I think the way they said the diode is for "GM vehicles originally equipped with breaker point ignitions" might be better worded something like "GM vehicles currently equipped with breaker point ignitions and that use the R terminal on the starter to bypass the resistor wire leading to the coil".