Above link is incorrect on a RAIV. There is no vacuum switch on the front pass water crossover on a '69 RAIV, instead just a pipe plug in its place. Been several years since worked on '69 RAIV Judge, here's what can remember.
-intake manifold has the common steel small fitting, this is on top of the intake in front of the Qjet. this fitting receives the vac hose going to the T'ed vaccum harness going to the RA upper pan asm, same as RAIII.
-rear of Qjet on center of the base (throttle body) accepts the vac fitting if the car has power brakes. This is either a straight through screw in steel or the straight potmetal fitting with one small port angling backwards ('68-71 style fitting). The large port in the back of the potmetal fitting accepts hose that goes to ck valve on the brake booster. the potmetal fitting with the small port, I believe was only used, when hideaway headlights were ordered.
-if car has manual drums, and std headlights, the port in the rear throttle body of the RA Qjet is blocked.
-that leaves the normal (single diaphragm vac advance) distributor, been too long since had a 7029273 in my hands, need to ck my 7040570, is there a ported vac source on the front of Qjet, drivers side? That's where believe vac signal for the #1941
distributor should come from. I can ck more on this, if needed.
-last, but common deal....if the car is automatic, there will be a port on pass side face of the float bowl of the Qjet. Small piece of rubber hose, then steel vac modulator line running back and down pass side of the T400.