[rocketraider]

In the 1972 Olds Chassis Manual- look on page 6K-10 (engine cooling), Fig 6K-19 which is for all 4-bbl engines except Toronado and 350 w/ manual trans. This shows vacuum hose routing for 350 2 and 4bbl automatics, and all 455's except Toronado if that makes it easier to understand.

Then look on page 6K-7, figure 6K-11 which is a picture of the switch itself, and identifies the four ports. An original equipment GM switch should have letters cast into it identifying the ports- C, V, D and M (which may be MT on some switches).

Connect hose from port M to the intake manifold as shown in 6K-19. This is bottom port on the switch. It tees into the manifold vacuum line to the transmission modulator.

Hose from port D goes to the distributor vacuum advance. This is middle port on the switch.

Hose from port V goes to the vent fitting at the top rear of the carb (one of these is choke fresh air intake, the other is the switch vent). This is the upper port on the side of the switch.

Hose from port C goes to vacuum port at driver's side base of the carburetor. This is the port on top of the switch.

Now that you know where each hose goes, do you need to know how the thing works? That electric plug on top has a lot to do with whether it functions as designed, or functions better for driving.

Page 6K-9 gives a complete description of its operation. If everything, vacuum and electric, is hooked up it will prevent any vacuum advance to the distributor until transmission is in high gear, but will also switch the distributor to manifold vacuum to advance timing if engine overheats at idle.

So, unless you're going for a concours restoration, I'd pull it out and use a non-electric distributor vacuum switch for a later engine. I think you'd be a lot happier with the driveability and fuel economy.