I'd say 12 lb-ft of torque and 8 horsepower gain on a V8 when the only thing that was done was go from a 1/16, 1/16", 3/16" ring setup to 1mm, 1mm, 2mm ring setup is pretty significant. It's easy to dismiss these values because you do a lot to an engine to come up with an additional 20 hp, when you aren't handcuffed to a rule book that regulates pretty much every aspect of an engine. It's when engine builders start experimenting with certain parameters everyone else just took as a rule of thumb, that new regulations wind up being made. This reminds me of a personal interest of mine, mechanical variable valve timing. Some of you might remember Varicam and Cam-A-Go from back in the 60's, that's the stuff that really interests me. Well, not that long ago, Suzuki wanted VVT in their racing bikes but electronic VVT was banned. So, Suzuki designed a mechanical VVT system that used centripetal force to overpower a plate type spring that would allow the timing to be changed. In racing, most gains in performance are small gains. Overtime, the small gains add up to a faster race car. Mazda several years ago started emphasizing on shaving grams off of every part in a vehicle. Big picture, the car would weigh hundreds of pounds less.
Small gains add up quickly.
