Starter "R" connection

So i bought a replacement starter for the R112 i have been trying to save. I know the starter was correct and would work on the SD 220 engine even though it was new and a newer style selenoid. This new starter has an "R" connection on the selenoid where the original one did not. From doing some reasearch the purpose of the "R" connection as it supplies a full 12v while the starter is engaged. It is supposed to supply a full 12v to the coil when the truck is being started and is isolated when starter is no longer engaged. My question is whether it would add starting benefit on the SD 220 that has been convert to 12v. Seems like it would add some additional power to the ignition it it has a step down resistor or coil with built in resistor. Thoughts? Anyone had experience with this?

No advantage with internal resistance, small advantage with external that would be bypassed. It was put in to provide a bypass to the ballast resistor that would not back feed anything when the ign is energized. It receives power only when the starter is activated and is completely isolated when it is not.