Of course it depends on the track (Occidental College for ex. has unusally long turns and short straighaways; the 1500m starts way down on the turn), but if we assume 100m straights and 100m turns:
We can make the 100m turn into a semi-circle, and using 2πr, we can estimate the radius of a circle with a 200m circ. at 31.830995m. So we're going to add 7m to the radius as we are 7 lanes out from the original radiusm, giving us a new radius of 38.830995m. Put this back into the formula of 2πr and we get the total distance of both lane 8 turns as 243.98228m, add this with the 2 100m straights and we get 443.98228m per lap in lane 8.
Of course I stopped taking math a long time ago so it's likely I screwed up somewhere.