74, L82, 4 speed trans - carburetor vacuum line installation

[Eric D.]

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Hello,
I looking for help routing the vacuum lines to the carburetor. The current installed carburetor is from a 77-79 Pontiac. I purchased a numbers matching date code correct carburetor. And, have installed what I believe is the factory installed TVS. The TVS has a port on the front, port on the passenger side with an electrical connection on the rear. This is electrical connection is connected to the engine wiring harness.

The Dr. Rebuild & AIM schematics show the vacuum ports on the L82, 4 speed carburetor. However, the carburetor I bought does not have a port on the front top passenger side of the carburetor; which per the AIM A.I.R. hose sheet 3, is where the diverter valve vacuum hose is plugged into.

I need to know that i have the correct carburetor and not a re-stamped incorrect carburetor for my car as well the correct TVS. If the are correct, how to correctly route the vacuum lines for my particular car. If not, get the correct carburetor and/or TVS.

Regards,
Eric

[Mark E.]

Re: 74, L82, 4 speed trans - carburetor vacuum line installation

Eric,

The AIM and Dr Rebuild diagrams you posted shows 4 vacuum ports just like what's on your carburetor: choke pull off connection, left front, right front, and one on the RH side. It's interesting AIM doesn't show the diverter valve connection..

Nice looking Quadrajet. My only nit-pic is the choke, secondary air valve, vent stack and a few other bits are not typically gold.

[Tom R.]

Re: 74, L82, 4 speed trans - carburetor vacuum line installation

I would suggest picking up the current edition of the 73/74 TIMJG, heavily researched with emphasis on the emission systems. Your carb is the correct P/N as well as broadcast code...FD as Mark notes! '

The TVS has a port on the front, port on the passenger side with an electrical connection on the rear. This is electrical connection is connected to the engine wiring harness.

The TVS does not sound like the typical 74 TVS switch...no electrical wire needed, given it operates on engine heat...Thermal Vacuum Switch!

The Dr. Rebuild & AIM schematics show the vacuum ports on the L82, 4 speed carburetor. However, the carburetor I bought does not have a port on the front top passenger side of the carburetor; which per the AIM A.I.R. hose sheet 3, is where the diverter valve vacuum hose is plugged into.

Below is an overhead view of an L48 with A.I.R. and shows the diverter valve hose connected to the front of the carb. I would surmise the L82 is connected likewise.

I need to know that i have the correct carburetor and not a re-stamped incorrect carburetor for my car as well the correct TVS. If the are correct, how to correctly route the vacuum lines for my particular car. If not, get the correct carburetor and/or TVS.

Your headed in the right direction...pick up the 73/74 TIMJG...its got over 666 images and schematics illustrating many of the emission connections.

emissions_L48_74.jpg

And the TVS for the EGR
TVS_EGR_switch.jpg