Mopar purple .520" cam?

Pulled a camshaft out of my dart's old 318 and was suprised to measure the lobes all were .345-.346" I have no idea how old or long the engine was put together. The previous owner had no info for me. I cannot seem to find much on it, I will check it with a degree wheel eventually, just wondering if there are any complete specs on it. Only numbers I can find are on the back end. 221000 and it is painted purple between the lobes. Thanks.