Required Preventive Maintenance For '77 450SEL V8 Gas

[Boydness]

I have not been able to find an FAQ or Guide for Required Preventive Maintenance for a '77 450SEL V8 Gas.

Just recently purchased a '77 450SEL V8 Gas that has 86K original miles. The car is in great running shape and I would like to keep it that way.

Other than a flakey power lock system, a collapsed lower cushion on the rear seat, and a slight leaking valve cover gasket, I do not see any issues.

Is there a Guide or something that would list everything that I should check and service?

Let me know please.

Boyd