[Mickey_D]

Depends on if you have the Silverado or the Custom Deluxe. A Silverado won't have too many empty slots in the fuse block like a Custom Deluxe will. Any empty fuse slot that runs an accessory that's only on with the ignition will work.

Some examples would be A/C, cruise control, fog/driving lights, power windows.

Some examples that WON'T work would be power mirrors, power seats, cargo lamp. (these are all things that have power 24/7)

If you find an empty slot that doesn't have any wires going to it, you can still use it. You just need get some crimp on wire connectors the right size for your fuse and figure out a way to get them to stay in the slots. Then you wire a "hot" lead in that's tapped into an ignition controlled source, and the other wire goes to the choke. But this is a lot of extra wire (and a possible chafe point going through the firewall).

I personally would tap in to the wiper motor power or the heater blower power under the hood. The choke heater isn't much in the way of a power drain, so one of those crimp on taps will work fine.

And you mentioned a fuse. You can get a fusible link from NAPA that you want to put as close to the tapping point as possible. A 5A or 7.5A fuse would be good.