cam identification

[DM69SS]

Hey guys - I have a couple of big block camshafts that I am trying to identify. Since you guys seem to know everything, I'll start here first. The first came looks pretty big. It has 4066 or 4068 cast into it. Hard to tell. It also has a marking of GM5 on it. It also has 2 raised dimples and another raised "M". Whatever it is it has a pretty aggressive profile. The second one is not nearly as aggressive and has a GM4 marking with a casting number of 6144. It has the same dimples along with the "M" as the above cam. It also must be from an early big block as it has the oil grove on the rear lobe. Thanks to anyone who can help!