Twin Cities Goal - 4:55:00, unsure it can be done

So my dad did the Twin Cities Marathon in 4:59 or so when he was 50 and I've felt like I need to beat his time and I can't seem to cross that barrier. What's wrong with wanting to beat your dad, I don't think there is anything wrong with that goal? Well I've run 4 marathons, Twin Cities twice and Grandma's twice and my fastest time is 5:11:21, I really need to figure out how to get the last 10 miles of the race at a faster pace.

Last week I did some interval training and this week I did some hills. I'm going to do a interval/hill rotation for the following 8 weeks of training which is really 6 weeks of training when you calculate in taper time. This means I've got 3 interval sessions left and 3 hill sessions left, 6-7 mid week long runs and 7 Thursday short runs.

My 17 mile run I averaged 11:24, some miles more some miles less but overall averaged 11:24. I looked at a pace chart and 11:30 gets you done in 5:01:31 so that extra 6 seconds per mile will actually get me done in less than 4:59 but not quite the 4:55 goal. I've got the following long runs left (18, 13, 19, 12, 20, 12, 8) I figure on the 18, 19, & 20 I need to average 11:20 and my 13, 12, 12, 8 I need to average 11 minute miles. In the final run I need to average 11:16 per mile to hit 4:55, I'm not sure its possible but I also know I can't hope and pray for it happen, I'll have to work my ass off to make it happen.

True test will be in White Bear Lake on 9/14, they have a great practice course that is 10 miles with twice around, great price, good water stops, and enough people to be running in a crowd. My goal for that run is to be DONE with 20 after 3:45, this seems SO DAM FAST but that only gives me 1:10 to get done with the last 6.2 miles, I just don't know if I have enough time to get it all in. Part of me wants to cry right now and part of me is motivated to get it done, I'll have to readjust my goal after my 20 mile run on 9/14. My biggest problem in previous years has been unrealistic finishing times. I'm really going to need family and friends to push me along the Twin Cities Course this year.