I have a 72 EC with the 402 BB. It has 65K miles on it. I have not been able to get this thing to idle smoothly since I bought it last September. I can see in the receipts from the previous owner that he had the pushrods and rocker arms replaced a few thousand miles ago. Has headers, and the original Q-jet and the TCS solenoid are all gone. Chased down a couple vacuum leaks and I have replaced the ignition wires, plugs, and cleaned and rebuilt the carb. It contines to run very rough when cold, backfires on light acceleration, and sometimes when you really get into it. I'm down to the cam. Wanted some other opinions before aI go for a new cam. I have been told these big blocks are subject to premature cam wear.