Exactly, the speed limit pulls let the poor guy be competitive. Horsepower rarely wins a speed limit pull, heck I've beat or been right with tractors that have at least 20hp more than me! That being said though, I'll be the first to admit that speed limit pulls are boring to watch.
Usually too much power hurts you in a speed limit class. It normally just blows the tires loose rather than lugging down and staying hooked to the track.
Yep, my very worn out tractors pull pretty good usually, in the pure farm/stock class. Just can't pull as heavy classes as the other guys, have to stop at 6500lbs with my M.