Looking for some guidance here. I have a recently rebuilt 440 with a slightly improved cam and msd ignition with billet distributor. Exhaust is stock manifolds with TTi exhaust pipes.

The carburetors are the aftermarket version of the correct 6 pack carbs. They were recently rebuilt and tested on the bench. All in all the carbs work well with no stumble under hard acceleration but the carbs were running rich at idle.

The car starts well either cold or hot but always runs rich. I closed the idle air/fuel mixture screws on both sides of the center carb and expected the car to stumble so I could start to adjust but no stumble occured and most of the rich gas smell went away. I also had to lower the curb idle screw so that the idle was at 900 while in drive with foot on the brake.

A friend tells me that I am not running on the idle circuit and the carb must be giving the engine gas in some other way.

Why is the carb running and idling well with the air fuel idle mix screws entirely closed? This seems strange but in reality the car seems to run well.

Also, any opinions on whether center fuel bowl breather tube should be connected by a hose to the valve cover breather or left unconnected and no hose.

thanks for all the help.