It would be tough for you...I ran 16:35 5k, 34:35 10k, 53:31 15k and a sub-effort 1:16:48 half and managed a 2:41:29 marathon on imperfect conditions (a little windy and warm but not too bad).
My prediction workout of choice was 7 x 1 mi @ sub 5:40 pace (jog 200 recovery) for a sub-2:40. This should be on a high-mileage week non-tapered (maybe a double that day). If you feel good, stretch the 1 mi to 2 or 3 but don't go much faster than 5:35 pace.