My vert slippage is 5.75%. I think a few here got the wrong idea about what I was getting at with the 470 vs 511. My point here was if I were starting fresh and had the option of building a 470 or a 511 for street duty, some track and to just tinker with I think the 470 would hit my goals of 700+hp with less money. From a mechanical stand point, just look at the design of the rotating assembly. The rod angles are better and the piston speed slower for the 470. The longer rod is the big deal here for the most part. With the shorter stroke your cylinders fire quicker behind each other in secession as well which I think would create better flow. It just seems to me it would be a more free spinning engine too. If ya think im wrong, just go over to Rerer&Morrison, they have an article on this subject. As far as CI aways making more power, in my case not so. My 408sb was faster and quicker than my 511.