[Dead Parrot]

The anti-dieseling solenoid was usually included on AC equipped trucks. It would bump up the idle speed when the AC comp kicked in. Some later emission motors had them because the idle timing was so low that the idle screw had to be screwed in so much the throttle plates were too open. When the power was off, the solenoid relaxed and let the throttle close.

The line from the carb front to the dizzy is normally the size of the one off the front top with the screw in it and is normally just a press on fit.

Might be a good idea to replace both the intake and valve cover gaskets. The PB booster can be a source of vacuum leak.

Check your idle timing as well.