C2 intake manifold opening

[Steve D.]

63 convertible, NOM, 461 manifold (64 and later? I was told)

There is threaded hole in the top of my intake manifold between the distributor and the carburetor (see picture). What was it's original purpose?
It was plugged when I bought the car.

Steve

[Jim T.]

Re: C2 intake manifold opening

The threaded hole is used for a fitting for vacuum source. Without my 64 since 1969 and having a 68 and 70, this location is used for my C3's for power brakes,vacuum for the vacuum storage tank to operate the multiple vacuum motors, and for the vacuum powered modulator on the turbo 400. If your 63 had power brakes this would be the souce of vacuum.

[Jack W.]

Re: C2 intake manifold opening

hole is for vac line fittings to PB and/or AC and/or Auto, as applicable, 64-67. If none such, the square headed plug is used.

[Paul L.]

Re: C2 intake manifold opening

Mine (1967) is Powerglide modulator valve and power brakes.