[Gearhead999]

The size of the carbs you're talking about aren't going to change the idle of the engine.

Have you checked for a vacumn leak?? Maybe pwr. brake booster, vac. advance, etc. Or maybe the intake manifold gaskets are leaking.

What type of vacumn do you pull at idle?? Where is the timing?? The float level will also effect the hot idle. This type stuff effects the idle quality also.