"What is your 8k time because if your running 6:30's on regular runs your not going to find a school that runs slower than that, at east not D1."
This is horses***, I am a sub 15:00 5k runner, have run sub 25:00 for 8k and I run slower than 7 min pace on almost all but workout days (unless I go a week or more without a workout). I know tons of much faster guys who do as well. Easy days 2 min/mile slower than 8k race pace is a good rule of thumb (this assumes you are running decent mileage). On a scale of 1 to 10, easy days should be a 2-4 and hard days an 8-9+. The best way to screw yourself is for easy days to be a 5-6 and hard days a 7-8. The key for easy days is more volume, not faster. If I had a dollar for every 27:00 8k runner who I have tried to go running with on a daily basis that runs too damn hard, but then sandbags workouts and gets smoked in races, I'd have a fair pile of cash. Christ, I rarely time an easy day and do a fair amount on trails that you couldn't possibly know how fast you are running.
Aerobic development occurs better at higher volumes on the low-end of aerobic pace, not lower volumes on the high end of aerobic pace. I still fail to understand the logic of thinking 6:30 pace is going to make one better able to race under 5:00 pace than 7:20 pace can. Both are so damn much slower than the race pace that you are obviously not working the "speed" system but rather laying the plumbing to exploit with other kinds of work. Sure, there are some guys for whom all aerobic paces are about the same in terms of recovery, but I reckon anyone who runs all their runs under 6:30 pace but can't race 8k in 5:00 pace is letting an insistance on "medium" runs get in the way of mileage (where the better aerobic benefits lie).