seeking nutritional hindsight

I'm still sorting out my race day nutrition even after having done this many times. Today I know I lost at least 3 minutes on the run due to serious stomach cramps. So toward fixing this, I seek input/knowledge in this area. Here's what I ate:

5am: 1 pkg instant oatmeal, 1 Clif bar, 1 banana, sipped 20 oz Cytomax from here to about 6 am.

7:35 Clifshot 100cal gel pouch
7:48 Race start
Sip 20 oz cytomax on bike
little bit h2o (maybe 4 -8 oz) during first 5k run
1 Clifshot gel ouch at 5 k followed by about 4 oz H2O at next aid station

Results: fine swim and bike, mild-moderate but tolerable cramp for first 6.5k of run, felt amazing and really took off next 2 k (about 6:30/m pace) mega cramp 1.5 k to go, could barely wimper in to finish line. Watched helplessly as about 6 guys in my cateory that I had kicked easily past up an incline, cruised past at the finish. Arrrgh. My run was slow at 7:11/m so I know it could have been faster, more like 6:40/m at least. Any suggestions about what I may have done wrong? This was my first Oly race in about 18 yrs but I seldom got it right back then either and we've learned a lot since then, I just seem not to have.