These calories should be from moderate to low glycemic index foods, and taken 3 to 4 hours prior to the start. You will want to limit the amount of fats and fiber to insure that you do not slow your digestion or risk GI distress. Some great options include Boost, Ensure, "Fuel for Fire" packets, bagel, unsweetened apple sauce with a scoop of whey protein, etc.
You should also continue to sip on sports drink and take a gel approx. 15-30 minutes prior to the start. Remember, nothing new on race day!
*Note: this is for a Sunday race. If the race is not on Sunday, adjust appropriately.