O.K. guys!!!! I have a 48 Chief (Bonneville). The plug in the front head is recessed in more than the rear plug (sits much deeper in the head). Is this the way they were designed? The front plug is much leaner than the rear plug. There are no leaks at the head or intake manifold. When I removed the head, there was significant carbon build-up in the combustion chamber. If I enrichen it any more the pipes get real sooty and the engine begins to load up. Any ideas????