How do I wire it? Had it wired into new harness for carb setup. Wiring doesn't kill engine. Rewired to ground and to negative side of coil. I have to push switch in to keep running. Seem opposite to me. Please help.

This is a new engine that was efi and converted to a carb 383.

You have it wired right, the switch is just wrong, you need to have a switch for a carb engine that closes
( provides a ground) when activated, the EFI’s ran this circuit through the ECM, not by grounding the net side of the coil