I'm planning on running an early September marathon and wanted to see if it's possible to run a 3:20. I have been averaging around 40-45 miles a week with a track work out on Tuesday, and some quicker progression runs around 8 miles that would get down under 7 min pace. On a recent 10 miler I ran I finished with 7:13 avg pace with a few miles below 7:00 min. I also have run a 5K after a long run (18 miles) last month under 21 min. My avg weekly runs are around 7:30-7:45 min per mile. Is it possible to hit around a 3:20 for the marathon, I have also ran a 1:34 half marathon in May, but blew around mile 10 as I went out closer to 6:40 pace.