Hi Pete, I was curious where i PA you are located. I'm in Reading. I also have a 440-4barrel in my 69 Imperial and in the owners manual it recommends premium fuel. Also, do you know what color the factory painted the motors prior to installing them in a vehicle? And is there a way to find out if the motor in my car now is the original one installed,I do have the original factory build slip if that helps. Thanks. T.L.