Next couple days I will be dialing in the carb. How long do I need to run at wide open to get a good read on the spark plugs? I plan running then shutting down at wide open and checking color. Unfortunatley I have 100 gallons of old gas and Im not sure if that will effect the tuning.

Bad gas will effect the motor tuning. You may not even be able to get to full rpm. It may even foul out the plugs. Also try to use old plugs as they will change color quicker.

When I dialed in my carb last year, it would only take 30-60 seconds at a specific rpm to get an accurate plug reading.

Also you should take plug readings at cruise speed/rpm also, before the secondaries open. You could actually overjet the secondaries and be lean at cruise speed if not.

A friend of mine is the chief engine builder for Andy Peatree's nascar teams and he told me to always do a plug check with champions spark plugs. They give you the best reading.

Save your engine from potiental dissaster and install an exhaust gas temp guage. Tune the motor to 1350 to 1400 degrees max. Livorsi marine makes a great kit. This will tell you what is happening at all throttle positions/ loads and takes the guess work out. my 02