I have had this problem with my 1951, low side cover style 216 motor. I have been through several head installations including a replacement because of a crack in the head. It doesn't leak a great deal, just a very small amount. I have the motor apart right now as I am getting the block bored .I have never figured out why it happens.
Last edited by truckernix; 01/29/2018 11:56 PM.