EGR, EFE, AIR What should I leave?

[Bob Chadwick]

I stayed with the Q'Jet. Has small primaries for fairly good fuel economy with large secondaries for the power when you need it. The only down side is it can be difficult to learn.

 

[photovette]

I stuck with the Quadrajet too--I installed a new Edelbrock Quadrajet. I love the sound it makes when the secondaries open--changing the carb to something else would take away some of the original driving experience--which is why I liked the car in the first place. Of course, the carb rests on a very healthy 355--that I consider improving the original experience--but, the sound of a wide open quadrajet is unique and I'd hate to lose it.

 

[celeryman22]

I stuck with the Quadrajet too--I installed a new Edelbrock Quadrajet. I love the sound it makes when the secondaries open--changing the carb to something else would take away some of the original driving experience--which is why I liked the car in the first place. Of course, the carb rests on a very healthy 355--that I consider improving the original experience--but, the sound of a wide open quadrajet is unique and I'd hate to lose it.

so do all Q-jets have the connections for the EGR and the only difference is model 1400 is set to run lean or whatever to meet emmisions standards.

 

[Bob Chadwick]

The connection for the EGR valve is simply a vacuum fitting. There are multiple vacuum fittings on the carb. Another is used for the vacuum advance for the distributor.

"Carburetor Vacuum Ports: Manifold, Ported and Venturi Vaccum Explained" by Lars Grimsrud is a good paper on how engine vacuum is used.

The Q'Jet was used in almost all of Chevy applications and can be slightly different for each application. For example, the 77 has multiple applications with some slight differences in jetting and metering. The L82 is different than the L48 and the auto with a/c was different than the manual. If have a replacement carb from a 76, which was on a pickup truck, which is slightly richer than the stock carb that was on the 77 L48 auto with a/c.