For all '60-'73 Slant-6 1bbl carbs (Holley 1920, Carter BBS, Stromberg W), plus '74-up Carter BBS carbs, use a kit № 1231.
All other 1974-up Slant-6 1bbl carbs (Holley 1945 and 6145) use a kit № 1234.
All Slant-6 2bbl carbs (Carter BBD, Holley 2280) take a № 1232.
These can be bought from CarbsOnly and Carburetor-Parts.com.
For my 2bbl setup, I ordered the № 1232 kit and here is what arrived:
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Electric_Choke_1232.jpg [ 98.22 KiB | Viewed 15679 times ]
The round black housing contains the thermostatic spring, and you can see it has two electrical terminals on it. The spring and housing are attached to the mounting bracket by a retainer ring and one or three screws. By loosening this screw, the housing can be rotated relative to the bracket through several whole revolutions, giving essentially infinite control over the initial spring/rod tension. The housing has a notch on it and the bracket has calibrated lines to help you keep track of your adjustment. As shipped, the unit was not preadjusted (no rod tension); I had to loosen the clampscrew and rotate the housing until tension developed in the pushrod.
You can see how the bracket attaches to the exhaust manifold in the same manner as the original choke. Other variants of the slant-6 choke kits have slightly different bracket fixing (2 holes instead of a bolt hole and a tab). This 2bbl kit has the pushrod with correct length and angles to connect to the factory type 2bbl installation—it looks wrong/weird, like it'll never fit or work, but everything fits and aligns correctly.
The black-and-copper device on the left side of the photos, in the middle of the bundle of wires, is the heat sensor. You mount this in a location where it's exposed to engine heat and gets a good ground via the copper mounting strap. This device senses engine heat and regulates power to the heating element inside the round black spring housing. The wires provided are nice and long, so you can experiment with different locations in the engine bay to find the one that gives you the right choke come-off rate. A good starting point is one of the threaded bolt holes in the top surface of the head, with the sensor box sticking up (not down) and hovering over the "ledge" of the head, above the manifold. If the choke comes off too quickly in that location, you can move it elsewhere (or just rotate it so less of it is directly above manifold heat).
had to go outside and look 