My uncle has a 66 GTO with a 400 motor in it. The person he bought it from said that he overhauled engine and put 500 miles in it. My uncle put another 150 miles on it. He changed the oil this weekend taking out the break in oil and putting in 10-40 oil. When first starts it runs 75 lbs of oil pressure but once engine gets warm it is between 5 and 10 at idle. When cruising down the road it runs 15 lbs of pressure @ 2000 rpm's Is this normal or is something wrong??
