[rbrtmchl]

I am in the process of adding Ram Air functionality to a 1974 Formula 455 (L75). One of the parts that I ordered from The Parts Place was an Intake Vacuum Fitting (p/n CB10811F). Their web site said the following:

INTAKE VACUUM FITTING - MOUNTS ON THE INTAKE MANIFOLD ON RUNNER #1. THIS WILL PROVIDE A STRONG VACUUM SOURCE TO OPERATE VACUUM ON RAM AIR AND NON RAM AIR CARS

When I went to install the Intake Vacuum Fitting, it was the wrong size (too small). I spoke with TPP and they said the part that I purchased is only good for cars up to 1972 (their web site says otherwise). They do not supply other sizes of the Intake Vacuum Fitting.

A few questions for the experts out there:

1) I have been unable to find the correct size Intake Vacuum Fitting at the normal parts suppliers (The Parts Place, Firebird Central, Ames, etc.) I also checked the website ‘Inline Tube’ but they don’t seem to have it either. I also tried O’Reilly’s and NAPA, but they didn’t have it. Would anyone know where to get the correct size part?

2) The standard non-Ram Air vacuum source for the air cleaner was at the back of the carburetor. If I am unable to locate the correct size Intake Vacuum Fitting, my back-up plan is to use this vacuum source for the Ram Air cleaner. Does anyone have any opinions or experience on whether this vacuum source will be sufficient?

3) For those of you with a ’74 455 with Ram Air, can you tell me what the factory vacuum source is? Did the factory use the manifold source near runner #1? Or at the carburetor?

A few pictures included for reference.

Appreciate any help and guidance that you can provide.

[Held for Ransom]

You need the vacuum switch. Air cleaner hose plugs in the top.

[rbrtmchl]

Originally Posted by Held for Ransom

You need the vacuum switch. Air cleaner hose plugs in the top.

Thanks very much for your response. So far I have only been searching for 'Intake Manifold Vacuum Fitting' and came up empty. Searching for 'Vacuum Switch' I came up with the following:

https://www.thepartsplaceinc.com/pro...19236477/96073

Is this the part that you are referring to?

[Kenth]

Look for "Ported Vacuum Switch Standard PVS8 ORIGINAL AC Delco 3030660".

http://www.pontiacpower.org/pdf/74ponticemissions.pdf

[rbrtmchl]

Originally Posted by Kenth

Look for "Ported Vacuum Switch Standard PVS8 ORIGINAL AC Delco 3030660".

http://www.pontiacpower.org/pdf/74ponticemissions.pdf

Thank you very much. Part found and ordered.