I have been working on my CD175 carbs for several months trying to properly tune and get them to operate normally without an erratic idle. To make a long story short, I attacked the ignition system by replacing everything. I also had a fresh valve job and rechecked my valve clearances. Finally, I purchased a master rebuild kit and very slowly rebuilt both Stromberg carbs to include the temperature compensators, chokes and throttle bypass valves. I ended up replacing the float needle valves twice. Timing was set to factory settings and the vacuum retard check for proper operation. The throttle linkage was checked and rechecked. After all this work and effort, I was still unable to get the dam thing to idle correctly. Finally today I followed the advice from Poolboy who suggested the disabling of the throttle bypass valves (TBV) as this is the most likely source of poor idle. I cut a small blocking gasket and remounted the valves in place. Sure enough, this action resulted in the car's idle being consistent and acting normally. I ran the car on some Texas back roads and found it to be responsive and predictable. In short, the problem was fixed simply by blocking the TBVs. I saw no adverse reaction to this technique and as long as the car continues to perform at its present level, I'm happy with it. Soooo, Thanks Poolboy and all the others who offered their advice.