Search for the "Tuning resuts with an O2 kit" thread, or a very similar title. I talked about one possibility in great detail with DaveNC.

If at cruise your throttle plates are barely open and in the transition slot area, and you have an engine with low idle vacuum/high cruise vacuum, you're seeing the common result.

Assuming that's true:

Use the smallest Idle Feed Restrictiors you can get away with.

Try lowering the primary float level below that of the top emulsion bleed. You'll need to take te front float bowl and metering block off and observe where the sight plug is in relation to the top e-bleed.

How many emulsion bleeds do you have in each side of your primary metering block?

Transition slot restrictors as a last resort.

If I misread the conditions under which the rich condition occurs, shout back.

J