HEI Vacuum Advance - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**samkost** · 09-20-2023, 05:24 PM

A friend came over to see the latest progress on my 72’ when he pointed out that my HEI and carburetor vacuum ports has been capped/plugged.
The carburetor manifold 3/16” port is also plugged.
Is a vacuum line needed for proper performance, timing and function?

Do I need to install a vacuum line HEI to Eldebrock?
The truck runs well but am I missing proper performance?
Truck runs well but is more power accessible with a vacuum line?

Rebuilt OE 350 V8 with Eldebrock Performer Intake, Eldebrock 1406 Carburetor and a mild Cam.
I never got model/parts numbers from the restoration shop from “Hell

“
That’s another story.

Thanks all

09-20-2023, 05:24 PM	#1
samkost Senior Member Join Date: Sep 2014 Location: Lake Tapps, Wa. Posts: 735	HEI Vacuum Advance A friend came over to see the latest progress on my 72’ when he pointed out that my HEI and carburetor vacuum ports has been capped/plugged. The carburetor manifold 3/16” port is also plugged. Is a vacuum line needed for proper performance, timing and function? Do I need to install a vacuum line HEI to Eldebrock? The truck runs well but am I missing proper performance? Truck runs well but is more power accessible with a vacuum line? Rebuilt OE 350 V8 with Eldebrock Performer Intake, Eldebrock 1406 Carburetor and a mild Cam. I never got model/parts numbers from the restoration shop from “Hell “ That’s another story. Thanks all Attached Images __________________ Sam 1972 C10 LWB, Hugger Orange/White 2025 GMC Sierra 1500 Elevation, Sterling Metalic



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