They're cool, no doubt. Just no torque. They look and run great on a static display stand but don't produce the suds needed to power anything.
I've seen miniature engines before; everything from radial aircraft engines to Ardun head Fords and Offys. They are neat, but useless for anything other than displays. My hat is off to the builders who spend countless hours building them however. They are no doubt dedicated and talented folks. That small block Chevy would be cool to own. But what do you do with it after it's built?
Tom