For people who swapped crossfire to carb
 

Have a 84 Vette , swapping out crossfire for carb setup, for the ones who done this already , where did you pick up 12 volt ignition hot wire for the new HEI distributor from

I did mine decades ago. If memory serves me correctly, I used the hot which went to the original HEI.

Correct, just use the factory tach and ignition pigtails and plug them into the new hei.