ok -- so I need more advice. I am having trouble adjusting the jets and setting the idling speed. Basically, I am finding it very difficult to get the idle down to anything below 900 RPM, and when it is there it idles very roughly. I can get it down by advancing the timing, but from what has been said in this topic, I don't think that is the solution. I set the jets at their initial setting (2.5 turns down from hitting the piston), and even with the throttle stops set so that they throttle is completely closed, it still idles at about 900 RPM.

I did find what I think is a vacuum leak -- in the small hose which comes from the end of a plastic unit mounted behind the carburetors, with a large hose coming from the intake manifold and a small hose going to what seems to be the heating control inside the dashboard. Where the small hose goes into the plastic unit (looks like 4 connected bubbles, about 2 inches wide each) it is held there with goop. When I shut the car off, it makes a sucking sound. So I put more goop on it, but will likely have to replace it.

Anyway, any thoughts as to why I am having trouble getting it to idle slowly and smoothly?

Also, how load is 'pinging'? Is it something you would definitely notice, or do you have to listen for it?