I've been looking at buying a '99 ford cargo van with a 5.4 motor. It has 150k on it auto with ac, manual windows , and no cruise. KBB on line says it's should cost approx $1800 retail from a private seller, and the NADA site says it should sell for More then twice the KBB value. The Nada sites doesn't let you select the motor option or other ones which effect the value in my opinion. So which one gives a more realistic price value?.,,