Hi, Just found the website and am looking forward to all the experience that is out there. I have a 1974 500 Cad in my 55 Chevy Pick up. I have been trying to get what seem to be an endless list of troubles figured out. When I pulled the engine out of a 74 as a 472. We put in a 500 crank totally rebuilt it. The first problem we found was it had the small chamber heads and we rebuilt it as having the large chamber. Way to much compression. Put on new heads with bigger valves and new rockers. Also found that one lobe of the cam had gone flat, replaced with a new one. I now have a knock that I can't seem to find, haven't had time to really dig into it, but I hope it isn't lifter or cam again. Seems to show up or get worse when under power going up a hill or giving it gas, but doesn't sound like a timing or gas knock (I could be wrong). The timing is set at 10 degrees, but just doesn't seem to be right. It shows right when using a timing light, but there are indications that it is off (rough idle, blow back when I shut it off sometimes, etc). Is there a expert that lives somewhere in Northern California. I sure would like to get this truck and engine running right.