Correct initial timing?
Agreed, but I don't want to be overheating or changing plugs on every cruise, either... Economy I'm not worried about (much). ;)
The locked timing should not be causing either of those problems. Its the retarded timing that gets things hotter than they should. The probem with locked timing at 34 will be starting. Whether your situation needs locked I can't say. Poke around on Speedtalk, racingfuelsystems, and motorsportvillage forums to find examples of when locked is advised.
Regarding the air needed at idle. An engine in neutral has only friction to overcome. They can be run very lean, and lean likes timing advanced as much as advanced timing likes lean. :) Unfortunately, need a bit more power to keep it running with any additional load at all. So with an automatic, set the idle timing and carb for best power in gear. With a clutch, its a little trickier since it can't be messed with in gear but concept still applies.
At the same time its very important that the throttle relationship to the transfer slot is correct at idle. For an older Holley, that's .020-.040" showing beneath the throttle blade. Some of the newer carbs, .040 is probably too much because the slots are longer or wider than the older Holleys. Anyway, if you find you've had to open the throttles more (using the idle speed screw), then find a way to let more air in so the throttles can be turned back down. Old school method was drill small holes in the throttle plates near the idle port. Some trick ways include the 'idle eze' which you can make yourself if you like. The throttle plate method has an advantage of bringing in the extra air near where the fuel is coming.
PS. You may not be done after getting the throttle position lower (assuming thats needed). I've found sometimes there is then a flat spot driving as throttle is increased. If so then richen up the idle and transition by sticking some wires in the idle air bleeds or changing them to smaller ones. Wires are just easy way to test. Make them long enough to hook over the choke tower (if there is one) and go under the aircleaner gasket. That way they can't get loose.
