I need some help determining which intake manifold vacuum fitting I need for my car. It is a 1968 RSSS BB AC AT (TH-400) Manual Steering and brakes. I know it needs to have at least one tube for the modulator valve from the transmission but not sure of the other stuff. Thanks!

Tim

There may be an extra nipple for A/C/Heating vents needed.

PCV valve in valve cover

Vacuum advance on distributer

Vacuum can for the light covers (RSSS)

Thats all I can think of right now... too early.

Doesn't the PCV and vacuum advance connect to the carb? I trying to figure out which fitting I need that screws into the back of the intake manifold. I know it needs one tube for the transmission modulating valve but not sure of any other connections at that fitting.

Sorry, I was confused on the question.
I run the PCV to back of carb and power brakes to manifold, but could go either way. Your not running power brakes so you could plug one of them.

Okay, I think I have figured it out from the assembly manual. I need a fitting that will accommodate the transmission modulator valve, RS vacuum canister, and AC equipment. The manual list part # 3891527. Anyone have an idea where I may find this fitting?

You might try www.hemmings.com and do a search.

Try an older recycle yard and most any GM product might have one.

People with 20- & 30-year bolt boxes would probably have one.