stumped again

[happy1970GMC]

So I've got good spark from the spark plug wire to the frame, I have rebuilt my quadrajet, #7043208, I have fresh gas and a new filter in the carburetor, the carter electric fuel pump seems to work fine, and the truck runs fine in the driveway--- for 20 minutes. I don't have a choke. There is a well in the intake manifold for a bimetallic spring, and a cable from the bottom of the dash, but it's not hooked to anything. According to Cliff Ruggles's book, this carb had a manual choke, I don't know if it's missing parts or what. I'd really like to be able to drive this truck, any help with what's wrong with it would be greatly appreciated.