Well, the Clyde body type lends itself to some kinds of riding more than others...specifically sprinting, which requires a burst of massive power, carefully timed, to blast to the finish line. If you watch pro races, all-arounders are very lean and typically smaller, climbers are very light, but sprinters look a little more like we do. In fact, I think some of them are pretty big (over 6 feet) and pushing clyde status.
Can you make a living as a rider at your height / weight? I think it's a loing shot. Can you compete effectively in some areas? I don't see why not.
I often ride with someone who is way leaner and much lighter than me (he's about 160, I'm 230 and 6'4 or so). I can't catch him on climbs or sustained flats, but I can outsprint him.