Back in the eighties, my family was friends with a Norwegian XC skier named TJ Sordal. Not Olympic level, but close. By the time we knew him he was essentially out of the sport and working for a company named Orthofeet that produced orthotic kits for podiatrists. Anyway, he was amazed at the (heavy) weight of the shoes I ran in including my racing flats. Now, we're talking Nike Spiridon's, which were probably around 6.5 ounces.
Making a long story short, he bought a used pair of Spiridon's from me and took a carving knife to the midsole and whittled away about 60% of the midsole & outsole. Then, he used a hole puncher to absolutely air condition the entire upper. When he was done, the shoes probably weighed 3.5 ounces each, and looked unwearable.
He ran a few times in these things, probably only 4 miles max at like a 5:30 pace on the roads. Keep in mind this guy's cardio system was still very intact from 20 years of XC skiing.
Well, I was entered in the 1985 NYC Marathon, and in those days the security wasn't quite as nuts at the start as it is now. After I got my race # from the NYRRC, I made TJ an exact duplicate of my number with, obviously, different numbers. So we ran the marathon, me doing a 3:46 (just getting over the flu) and TJ being right with Grete thru halfway and then getting pulled off the course in the last mile on about 3:05 pace (the only reason he got pulled off the course was that I made his number with WATER SOLUBLE magic markers and the ink was running down his shirt...oops!).
I think I recall TJ saying he woulda outrun the NYRRC police if the shoes he had on (the mutilated Spiridon's) were just a little lighter.