I found this C&D article from last December and thought it was a good read.
They race one of Jay Leno's rides that uses a 29.3L V12 tank engine against an M1 Abrams.
http://www.caranddriver.com/article....&page_number=1

 

What's the point of that rod? To empty teh world's fuel suppy faster?

 

and because tank engines are cool

Do hot rods need to be justified?

 

Instead of 2 or 3 mpg, the Tankrod's mileage rocketed to about 5. "You know," says Leno, "it's Southern California. You want to do what you can for the environment and everything . . ."—he spots a gas station—"Hey, let's throw in a quick hundred." Climbing out, we both step carefully lest we liquefy a limb on the exhaust pipe.

 

That thing is awesome. I have it on GT4. Win the tests 11-20 and you can have one too.

 

Damn...Leno's collection never fails to amuse me.