I have a 1985 305 engine with a Quadrajet carb. I rebuilt the carb and it currently idles at 850 rpm with about 16” vacuum at the brake booster. The engine has no issue starting, but when the transmission is in gear the engine sounds terrible. I am not sure what the vacuum does or how the rpm respond. The transmission is a 350th. What adjustment need to be made to make engine run smother in gear.