Don't run it without oil.
Change the oil at 1500 mile intervals.
Don't run it with advanced timing.
Keep the chain lubed.
Keep stock sprocket ratio.
It will run 80 MPH without complaint for years.
The 77 K model has lean burn carbs, which makes the engine run a bit hotter than prior years. Stock paper air filter and exhaust are still fine with these bikes. But, pod filters and aftermarket exhaust can make the engine even leaner and hotter. The extra heat will shorten it's life. An oil cooler may help extend the oil's life expectancy, but won't help the engine cylinder temps from a lean burn engine.
If your test runs at 80 mph leave chocolate brown spark plug insulators evenly across the cylinder bank, ride it and don't worry.
If your plug temperatures are elevated (white/near white), you should consider an oil that has higher breakdown temps as well. Blend your own if cost is a factor. A little PAO base oil will still lube at high temps and the extra lubrication will keep friction down, resulting lower temps and increased engine life. Even a one quarter blend will help extend endurance.
Cheers,