6 pak run bad cold

Hi All, I have just started my 440-6 for the first time after a complete rebuild. It was an original 440-6, and I assembled it mostly to stock 70 specs. I removed the exhaust heat riser and used the block off valley pan. It will not idle until quite warm, I mean about 15 minutes of working the throttle until it will idle near 850-900 which is factory spec. I have 12 degrees of initial advance, I have the stock 6 pac resto cam, it pulls around 13 inches, I do not think there is a vaccum leak.
I have a mopar performance electronic distributor. The carbs are the new holly 2300s for the 6 pac set up. I installed them out of the box. I did check the float level, and adjusted the idle circuit. Anyone have any ideas? If I advance it to danger levels, it will hold an idle, but then I will have other problems.

Thank you for any input you can give


Rich

Rich