I drained the oil this evening and pulled the oil bag to give it a good cleaning. Judging solely from the shit that was caked to the outside I'd guess it's never been done. I'm going to give it a good gas-bath in the next few days to break up some of the sludge that's built up inside over the last 30 years.
I picked up some oil hose in anticipation of running all new lines. What better time than when I have it drained? I'm also planning on simplifying the oil system some by removing the cooler and sealing my primary.
In most (or all??) stock shovelheads, the primary chain is lubed by the engine oil inside an enclosed "outer primary" which houses the chain and clutch plates. When oil leaves the primary enclosure, it's dumped directly back into the motor without being filtered, carrying along with it any contaminants from the chain or clutch plates (metal shavings, clutch dust, etc). That shit can be bad news for the life expectancy of the motor.
By removing select supply and return oil lines and plugging fittings, you can isolate the primary from the rest of the oil system and "seal it up". You give it a bath of it's own lubrication (I'll likely end up using normal old transmission fluid so I can spot leaks easily) and... problem solved!
Pics and progress updates soon...