"P" is for power take off, same size as a MD 3060 as the power take off runs off the converter
Non PTO 3000 series is 28.29" long and weighs 535lbs.PTO version is 32.49" long and weighs 575lbs.
www.utxchange.com is a easy place to get the info all the specs for different Allison's are there, I believe all models of the 3060 takes a #2 bellhousing also but if it is a generation 1 or 2 I would pass If it has the shift tower instead of the touch pad I would be interested in buying the tower