Tav - while researching this other current topic on '70 E Body relays & delays, etc I came across this a/c vacuumm delay below.

When used, it was probably installed through that second unused hole in the vacuum grommet that we didn't know what it was for. Any opinions? Have any clue what the delay actually does and under what circumstances it was installed?

This style grommet was found to be used on E-bodies where the heater gontrol cable passed thru as opposed to the drivers side of the firewall

This style grommet only the vacuum source passed thru. And the heater control cable passed thru the firewall using a hollow nail for the firewall insulation to the left of the steering column.

I originaly suspected that the heater control cable passed through that, but my car was missing the cable when I bought it.

I had tried to route a cable through that area once, and had trouble with it binding due to small radius bends in the cable. Does anyone have some pictures of the correct routing for a cable using this grommet?

Is this cable the same length as the one that exits the firewall by the driver?

My cars SPD is 8-26-69 and it had this grommet for the cable to pass through. Is there a rough date available for the switchover, or is it more of a plant/vendor thing?

Thanks
Tav