Help Identifying this Block

I bought this block a few years back from a guy that didnt know what it came out of. Was wondering if anyone could help with year its from. I think its a roller block which makes me wonder why I am running into issues with the lifters coming up past the galley holes, but I want to find out for sure on the block before I go any farther.
The numbers on the side are 53020006-360.
Thanks in advance for your help
Rodney