so for a 8 mile tempo run my ave HR is ~165, max HR is 186 - is this OK or am i running them too hard?
they feel "comfortably hard" but that's not exactly a scientific explanation.....
(i'm using paces from daniels based on a recent race and adjusting tempo pace for distance for longer tempos like he suggests.)
This is one thing that bothers me when people read Daniels:
The paces are guidelines, not necessarily what works best for you. You might get more benefit at 170 or more benefit at 162, every person is different.
165 is fine, but the important thing is not to stress it and just aim to be in a range. Focus more on your running and less on your heartrate.
Remember, you will get benefit out of the tempo at 160,161,162,163... so on and so forth (as long as your not racing it).
That depends on how you intend for you post to be interpreted:
"Avg 165 during Tempo, Max 186 during Tempo"
You would definitely be running way too hard. Or varying your pace too wildly. I hope this isn't what you meant, but the way it's phrased is unclear.
"Avg 165 during Tempo, Max 186 Overall"
This sounds about right, so long as the effort is okay (comfortably hard is perfect).