I'm in the process of replacing the Plenum on my 1998 K1500. I have all the connectors labeled that I disconnected, but I cant seem to find one for this port.

What connects to this opening with the red arrow?

Chevy 262 Plenum

  • 1
    Have you plugged in the vacuum line to the brake booster? This is a rather large port (and it is ported for vacuum). It would most likely be one of two things, either the brake booster or PCV. If you've found all of your ported stuff you took off, block this with a plug for now and give it a go. It could be this is an extra port for newer models (or older ones), which isn't used on your vehicle. Sep 12, 2021 at 17:25

2 Answers 2


I'm a dork. Its for the Vapor Canister Purge Valve, which I left hanging out of the engine bay and didn't see it while looking at connectors.

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Some ports or holes can be those used during machining to get all the others in the correct locations.

Or it could be where locating studs fit.

Or, if you check with the gasket, that one could actually be blanked.

Best way is to take pictures before taking things apart if it is the first time.

  • I did take photos, but unfortunately I was focused on the studs and wire connections. If there was something there I skipped it. This is how the bottom of the old one looks: imgur.com/a/RU5fK5O
    – ak_
    Sep 12, 2021 at 23:35

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