I agree that this is a nicely preserved '64 Imperial and I like it in the $5k-$6k price range. The '64 is one of my favorite Imperials. There are some obvious things that hold down the value of this particular car. The seats being redone in vinyl is a real turn off to any Imperial purist. The leather interiors of these cars were gorgeous and comfortable and among the best in the business. Not hard to understand why the interior was redone in vinyl as the proper leather for this car is about a $5500 to $7500 job. Factory leather never went bad at the 20k mileage mark, so this is likely a 120k car given the very dirty condition of the engine compartment.
The other thing that leaps out at me is the "conversion" to R-134a. The compressor has a blue cap on the suction line. A licensed shop would have installed the proper snap couplings on the high and low side of the compressor to insure that no one tried to recharge the system with R-12 at some future date. That suggests to me that someone might well have charged the system in their back yard or garage without doing the proper removal of the R-12 mineral oil in the system. The rear evaporator on these cars collected lots of oil and it usually is difficult to remove it without pulling the evaporator and flushing it. I suspect this A/C system is living on borrowed time if it still works at all. If as I suspect, this system was not properly flushed, it will have oil that is snotted up by now and it will be time consuming and expensive to bring it back to working order.
Assuming one has no need for working A/C, this car is still a good candidate for a nice "driver" at $5-$6k.
Dave