I want to modify one of my QJ's so that the secondary air valve opens fully.
A)How critical is it to have the opening angle just right? If it's critical, what is the best way to measure it?

B) Are all the cams that the secondary rod hangers ride on the same? Do I need to change the cam?

I usually file the stop so that the lower part of the air valve go just about vertical. I`m not positive if it`s the right way but I do it.

Jim

for the air valve there's a stop on the front of the shaft on the passenger side. file,grind/bend till it opens all the way. I do this on every carb, along with bending/adjusting the link on the sec throttle shaft on the driver side to get full throttle opening.

a few degrees on either is not a big deal, just get so it's visually vertical when wide open.

Tom

I was concerned about going far enough to make the bottom edge verticle. The forward edge curves up and by going verticle on the bottom the top edge is blocking the airstream a little. I am probably being nit-picky, but I adjusted it so that the SHAFT rotates about 85 degrees.

The lower part of the air valve combines with the secondary baffle to create a venturi. If it opens too wide, the air valve will shadow the main discharge nozzles, affecting the secondary mixture. The stop is usually set with the upper portion in the vertical.

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67 Nova 3475# daily driver
10:1 406, 700R4, 224° Comp cam, RPM and a Q-jet - 11.75 @ 117
67 Nova Wagon under construction
65 Corvette Road Racer