Is this an air flow sensor?
There is an electrical connection.
One side connected to vacuum advance, the other the front vacuum port next to the DS idle mixture screw.
There is another connection on it, but l have it plugged.
Didn't seem to make a difference plugged or not.
Is it supposed to be connected somewhere?

71 340 application

California car?

If so see the page at https://www.hamtramck-historical.co...ssengerCarHighlights01.shtml?load_img=39

I believe it to be a retard mechanism. I haven't seen one on a small block but on big blocks in the early '70's. I believe it prevents vacuum advance in 1st and 2nd gear for emission purposes. At least that's how GM approached it those days, GM called it TCS, or transmission controlled spark. Theirs was easy to bypass, just bypass the solenoid with a piece of vacuum tube.

Thanks for the replies, and the link Barry.
Yes it is a CA car from my knowledge.

I did try bypassing it. Didn't seem to make a difference at idle.
Am trying to get the car tuned properly, and going through all the connections.
I will likely keep it bypassed , to eliminate variables.