In-gear idle issues

Here are some additional details:

• Unfortunately the cam specs are long gone
• I am running ported vacuum advance
• With advance hose plugged, timing at idle is advanced 25 degrees @825 RPM
• The (carb) blue hose goes to vacuum gauge, left to distributor, and middle is split to valve cover and charcoal return line
• Timing
• Putting into gear

Thank you in advance