Brian, from what I found, it's a Case 580C.
The local shop that has rebuilt a few of my SEE and HMMH cylinders concluded that it's dirt buildup and lack of use that caused the leaks, except for one where a poor masking job had left a chunk of OD paint on the rod.
Since then I've cleaned off the appropriate areas and put some oil on the seals. No new leaks since.
And, yes, your fans should come on after a while, especially if you run higher rpms.
I'm down to one functional fan, and will try finding the problem this week as it's gotten hot here.