Where to start - maintenance on a 340

Hey yall.

I'm digging into the 71 Dart Swinger my pops had. It's basically been sitting for 10 years since he passed.

The car runs and sounds pretty great currently.

I'm wanting to go through and complete basic maintenance on the engine such as replacing all gaskets, fluids, filters, etc.

The motor was built by a performance shop over 25ish years ago and the spec sheets have long since been lost.

I know the cam was custom ground and a ton more was done.

My question is this, if something needs replaced how do I go about learning the specs of something like a custom ground cam? Would

The rocker arms seem to have a bit of play in them, I've heard that some is normal, but what about this much?

The car was raced back in the day and has a nitrous retard and delay installed alongside the 6AL ignition. Can those just be disconnected? Is there anything else that needs to be done to remove them? (The nitrous has been removed already.)

Thanks for any help in advance.

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