Was looking at a 1970 RM21 hemi car yesterday. It was said to have the original motor in it. It has been owned by the same person since the early 70's. The only number I was able to get a picture of was on the top boss. I am not familiar with what is or should be stamped here. It looks like the number has a G in front of it. Does this ID it as a '71 motor? What do these markings mean?