Anybody Recognize this Cam #?

I recently bought a 383 that has had some work done to it in the past, but no documentation.

The only marking we can find on the cam is the number 633870. Google shows nothing with that number, and the machinist can't find anything.
I'm thinking maybe it is a partial with some numbers missing from one end of the other. Does anyone recognize this sequence?

Extra hint: It appears to have been built as a high grade (Forged pistons, ARP hardware) slightly improved street engine. Nothing racey at all.

TIA