Thanks 426HEMIDAVE. It would seem the '69 Six Pack blocks don't have the magical "C". I've encountered three '70 six pack blocks that all did. I've got one in my garage right now. You're also correct about the other '70 440 engines, they don't all have the six pack rods. I own a factory '70 440 "U" code 'Cuda HP that does NOT have six pack rods in the engine. There may be no way of clearly telling a '69 Six pack from a 4 bbl. engine except for the VIN. The "C" started appearing in the 1970 engines.