holley 1920 choke thermostat

You can either buy an original choke thermostat with the mechanical spring inside of it or you can buy an electric choke pull off.

The only downside to an original choke thermostat is that they aren't adjustable. It could keep your choke on for an extra 5 minutes which wastes your gas. I opted for the electric on mine. It doesn't look as clean or original, but it's adjustable and allows me to pull the choke off as quickly as possible. The weather is mild on our side of the country and we only need the choke to be on for a minute or two.

If you want an original type, I might have one in my garage that you can have for free if you're ever in the Sacramento area.