Basically what the title says. Doing a motor swap and want to adjust shift points. Kit didn't come with aby rods to change the springs so I can't cut em without spending more money. What do I do? Is there a way to install them without doing that?

If all you're doing is changing the springs, then no, you don't need to pull the pins. Just need a pair of needle nose pliers to pinch the spring and pull it out. If you need to change the weights, then you would need to replace the rods.

What nails do I need to replace the pins? A couple videos online say to use a 4D finishing nail.

Trying to update to the black and red springs (currently has black and blue), per the Transgo 700 kit, but the kit did not furnish new pins/nails.

4D are 1.5" and too short.
5D are 1.75" which is very close to the length needed, but again, just a bit too short (not enough meat to bend OR flatten the point to keep the nail from falling out.
6D are 2", and probably the length needed (could actually cut them down a smidge), but are too thick to fit through the governor hinge holes.

Thoughts form anyone that has done governor mods?