I recently bought a 496 c.i. motor, built with 14:1 pistons, Callies forged crank, Dart Pro 1 heads (310). Recently assembled, with no miles on it. I installed it, made a couple passes, and found the motor was blowing a little oil out of the intake, I decided to pull the heads off.....just to check things out. The motor is a 1969 427 4 bolt main....according to the research I've done on it. Everything looks o.k., but the deck of the block has 0-ring grooves with no o-rings in them. I never heard of this procedure before, but a lot of you may have. I talked to the guy I purchased this motor from, and he said it was an old race motor, and that was done years ago. I need some opinions. Should I just put it back together with the Felpro Blue head gaskets, or should I look for another block. I have 2 different engine builders telling me conflicting opinions. I figured I would try the really knowledgeable people on this forum. Any input will be appreciated. Thanks. Oh.... I should mention.......I found no noticeable head gasket leaks when I tore the motor apart, but keep in mind....there was very little running time on this motor.