Accel 52301 street billet sb distributor

About the connector, it looks like you need a 3-pin Weather pack. The are available many places, used on GM cars. You will need female housing, pins and wire seals, kits are available. The correct crimper helps too. Not sure why you think you need vacuum advance lockout, that is automatic when you mash throttle down.If you want it locked full time, pull the hose.
Weatherpack.com