Mopar single bolts cam are 7/16 course, I didn't know or worry about cam walk back then The oil pump drive gear will limit the fore and aft movement of the cam some what I now use a dial indicator on one of the cam lobes without any of the lifters in the block and see how much forward and rearward movement it has, if it is less than .005 I'm golden If more than that I try to get it so it is less than .005 total