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Dynomometers are by and large useless. Why do we say this when they're obviously valuable for tuning? We say it because they've ruined so many performance-oriented enthusiast mags, turning them into numbers-fests. "Eight Billion Horsepower at Unusable Revs Exclusive! Part XIII!" What if you could simply do your own dyno-fiddling at home? While far from factoring variables beyond intake manifold, rockers, cam, carb and heads, GM's little virtual dyno toy is pretty cool. Check it. [Thanks to Manny for the tip.]

The Ultimate Online Engine Builder! [GM Performance Parts]

What's the Greatest American V8 of All Time? [Internal]