[James]

The ported vacuum (timed spark vacuum port) on the choke side in the metering block does nothing on the 4412, the throttle plate base does not have the hole in to allow that to work. I had drill the hole in my throttle plate base and the gasket to allow this feature to work on the metering block. Depending on how old your 4412 is, the ported vacuum is either on the metering block or on the throttle plate base below the choke or both. If it is on the throttle plate base it should be functional. Back in the day (correct me if I'm wrong) all of the distributor vacuum cans went to manifold vacuum. So that third fitting (on the front of the throttle plate base) I believe is manifold vacuum, if that what you have that is where the distributor vacuum can gets connected to. With tighter emission it got moved to ported vacuum. If you chose to use ported vacuum you have to readjust the idle up and maybe advance the distributor timing a few degrees from specs.

As for the throttle return spring, buy any spring that will give enough pull to keep the throttle close and still allow full throttle. The one on the carburetor normally not enough to keep the throttle close once installed on the manifold.

On the subject of fuel, did the engine start after you got home? Have you check the fuel pressure with a gauge tee in? Did you check the fuel level in the fuel bowl after you been cranking for a few seconds (without pumping the throttle)?

Let us know what you figure out.