I've never subscribed to the theory that bigger must be better (certain aspects of the female anatomy included). Nevertheless I've often been awestruck by magnificent autos that were overwhelming due to their luxury or performance. In the latter group were vehicles whose creators determined to build the fastest-in-a-straight-line cars by adding huge engines to one-off specials. Most such engines came from aircraft including, or especially, the Merlin V-12's built by Rolls-Royce for Spitfires, Lancasters, Mosquitos and later adapted to P-51 Mustangs when Packard's Allison engines failed to perform well at high altitudes.

The 2008 Pebble BeachConcours d'Elegance will be honouring four 20-liter-plus cars (1,220 cubic inches) in a one-time-only showing. On display will be the only long-chassis 200 hp "Blitzen" Benz... a custom Rolls-Royce modified to fit a massive 27-liter Rolls-Royce Merlin aircraft engine taken directly from a P-51 fighter... and a car utilizing the same P-51-type engine on a hand-fabricated chassis known as the 1953 Swandean Spitfire Special. Standing out as the sole modern offering will be Jay Leno's entirely custom tank car, aptly named for the 30-liter V-12 Chrysler-built engine derived from an M-47 Patton tank.

Leno admits: "It's just ridiculous and probably the most inefficient fueled vehicle ever devised. There's no practical purpose to it other than it's just fun and people get a kick out of seeing it. In an era where things are getting smaller and smaller, this is a throwback to a time when things were really, really big." While Leno's car is entirely custom built, with a wheelbase of more than 15 feet, early race car expert and longtime Pebble Beach entrant George Wingard's 1913 200 hp Blitzen Benz is one of the largest examples of early factory efforts to boost performance by increasing displacement. One of six famed Blitzen Benz cars, and the only one built with an extended chassis and a four-seat body, it set multiple speed-records throughout the 1920s.

"Early race car engines were almost always four cylinders," said Wingard. "Until manufacturers discovered engine balancing, increasing power meant increasing engine size, which resulted in cars that created tremendous amounts of torque. The power in the Benz submerges you into the seat and driving it is like nothing you've ever experienced."

"This is a tongue-and-cheek class not based on anything but fun," said Leno. "I go every year to the Concours - it's the premier event of the year. The nice thing is that no matter how big of a car fan you are, I almost guarantee that every year there is a car you've never heard of that was built in some obscure period in Bulgaria... or wherever. "I'm not even sure my car will be able to make it around the corner down there at Pebble Beach, so we'll see what happens."