I want to wire in a kill switch inline with the power wire to my HEI. How much current is drawn by the HEI unit? Do I have to be careful about how much current the switch is rated for? Thanks for any help.

It seems to me I read somewhere it draws 1A per 1,000 RPM ?. Let's say it even draws 5A per 1,000 RPM which I kinda doubt considering the factory wire size. OK, so let's say a 6,000 top RPM. This would equal 30A. I would get a switch rated for 30A but let me throw this out to you. Since all wire lengths and connections will have voltage drops, why not wire a 30A
continuous/40A momentary relay inline on the existing wire going to the HEI and bury it by the bulkhead connector on the firewall by the brake booster or behind the fender behind the front inner wheel housing. You could now run a ground wire off of a particular terminal on the relay and run a basic 1A or so switch and not have any live wires run into the interior that if possibly became shorted could cause an electrical meltdown or fire. If you get a particular relay socket the socket would be mounted to the car and as an added security benefit you could take the relay out of the socket to where even if someone would know where the interior switch was at the car wouldn't run. Also too if the relay would fail you could fashion a jumper wire with 2-1/4" male terminals on it to where you could pull the relay out of the socket and then jumper the HEI feed wire from the ignition switch to the HEI and the car would be able to run.
If you do extend the HEI power wire into the interior use rubber grommets where the wire passes through metal, maybe add an inline fuse where the HEI wire is getting power from, and buy a good quality toggle switch for reliability and if posible make solid and secure connections.
Cheap switches and switches not rated (or have inflated ratings) are not good investements and will fail at the most inopertune time. Steer away from the plastic housing/plastic handles ones for a few bucks each.
Jim

Just a factory stock HEI?
Can't be much, judging fom the wire size normally feeding them.
A relay with a ground leg to the switch is a good idea.