Holley Carb Problems

[landy]

I bought a '71 GMC 1500 with 350 engine and manual trans. Came with a Holley street performer 4 bbl w/vacuum secondaries and electric choke.

I can't get the idle speed down to below 1000 rpm or so and could use some suggestions. Here are the details:

Carb looks pretty new. Truck runs great. Starts easily when cold.

Adjusted the timing to factory specs. It was way off so that helped bring the idle down. Checked for vacuum leaks. Backed out the idle speed screw, disconnected the return spring, and made sure the throttle linkage was all the way forward. Backed out the fast idle speed screw all the way. Adjusted the idle mixture screws in and out, which made little difference on the idle speed and vacuum readings. Vacuum gauge is reading around 14 in at current idle speed.

Ah, the choke. When engine is completely warmed up, choke blade is not completely vertical as it should be. The choke linkage is set up such that it can't open completely. If a blade that's open all the way is 90 degrees from horizontal, this one opens a max of 65 to 75 degrees - maybe that's the way Holleys are set up? The bottom of the choke blade rod sits on top of the fast idle cam, so it can't open any further. I'm wondering if I need to bend the rod so that the choke can open all the way as I see no other means of adjustment. Exhaust does smell rich and maybe that's because the choke blade isn't open all the way.

Any thoughts?