Taking 800 mg Ibuprofin or other pain reliever before marathon race?

OK fellow runners, I want to run the race of my life - and my calfs really start to bother me when I run hard for 26.2 - I'm looking for an advantage to alleviate the muscle pain that may slow me down in a race I will be running in March. I am in great shape and am shooting for a sub 3 hr time - but at about the half way mark I my calfs really start to feel it. From a cardio vascular point of view - I'm fine and not winded. My pre race and in race nutrition and hydration are excellent, so they are not an factor. I am very interested to know if others have tried this and to hear of there results? Downside? Upside? My calf muscles are like rocks, I do plenty of distance at race pace in training, as well as strength training, but the calf issue is something I have not been able to overcome as far as the soreness after running really hard for a long distance. I can run through the pain, but it slows me down. It is not excrutiating pain by any means, just a dull ache that gets progressively more intense as the race progresses. Also, if you used a pain reliever other than Ibuprofin, I would be interested to know the results as well. Thanks for your help and keep on running!