Jay Lenos W109 gets an M156

Jay Leno has at least one thing in common with one of the cars in his famed garage. Underneath the understated, beautiful exterior lies something much less, um, feminine.

Everybody knows Jay Leno is the pentultimate car guy. I got to meet him last night at his garage, during a party that he and Mercedes-Benz threw to help celebrate the launch of the new SLS AMG, the reborn Gullwing. He showed me his dyno room. I want a dyno room.

While we were there, AMG presented Jay with a gift–a brand-new, shiny M156–AMG’s “6.3-liter” V-8. (The engine actually displaces 6208cc, so it’s technically a 6.2-liter. But you already knew that.)

Jay asked for help getting the engine for his 300,000-mile W109 300SEL 6.3… the engine is tired and he wants a power bump for it.

How cool is that? Okay, if you don’t know much about the original 6.3, you should look it up–it was the world’s fastest sedan way back when. And it’s probably safe to say that Jay’s car will be the fastest 6.3 when he’s done with it. Read Jamie Kitman’s story of a road trip in his own 6.3 here.

AMG built the engine specially for Jay, replete with his name written on the plaque that always identifies the man who built the motor (AMG builds the engines using a one-man one-motor technique, and each engine gets a plaque with the name of the guy who built it). Mercedes is also going to supply a 7-speed automatic and all of the computers and custom programming to run the thing.

That means that Jay’s 6.3 will have Keyless Go.

I’d call that Keyless Goooo–oh My God. I can’t wait until he’s done with it — and if I have to camp out at his garage, I just want to see it all done. This is easily one of the coolest motor swaps I’ve seen. And not just because that new 6.2-liter V-8 would probably cost you $40,000 if you walked into a Benz dealership to buy one. No, because it’s taking an old 300-hp rocket, giving it more than 500 horsepower, and nearly doubling the number of gears in the transmission — while still saying (reasonably) true to its 6.3 badge.

Bravo to Jay for hatching this evil plan — and to Mercedes for helping him pull it through.