Is there some way that you could get together with a "local" Brickboard member and do some communal head scratching (ROAD TRIP). I know that this has helped me out quite a bit as I've helped out on occasion with a few and received assistance back - great "local" group (250 KM radius).

If the shafts are not leaking and you're sure the fuel bowls are fuel tight, then where is the fuel going? When you say that the shafts are tight, is that measured with them off the manifold? There should be a few thou of play to the shafts - ie, you can get the shafts in without forcing them, but there is no side to side play. Just a little side to side is too much. This play will be taken up when the carbs are installed, but the vacuum leak is still there. That's the reason for the seals on the HIF's.

I personally use a propane torch (unlit of course) to find leaks around the manifold. There will be a slight rise in RPM with any leak and I don't think it is dangerous. What about other sources of potential leakage? What about the jets...are they still round? I'm still having trouble trying to figure out why your idle would stay high - it is basically throttle controlled. You either have an air leak, fuel leak or both if you can't dial them back to a stall.

A head scratcher for sure.