I wish now that I would of rebuilt the sludged up 76 351 I had since it had never been apart,I think the builder just pieced it togather from whatever he could find. I was thinking that maybe the heads had been milled and the intake is not sealing properly so I am thinking about a head,cam and intake set if the cost is not prohibitive. I am going to put a gauge on it today and see what it reads,its acts like I have the vacumn lines on a port above the carb but I have them on the manifold. Jeff