"I hate replicars," Hans Glaser blustered at me. "By the time you’re done, you’ve spent almost as much as for the real thing, everybody 50 years ago was building their own car in a shop or garage. Today it’s too expensive."
That sturm und drang about replicars was the result of probing the legitimacy of Hans’ masterwork, a unique Jag V12-powered XK120.

Glaser is a fervent Jaguar enthusiast, a Vintage Jaguar racer of some reputation and a professional restorer of the Coventry cats. He’s a man who gains deep satisfaction from driving and working on automobiles. A German who emigrated to California via London, Hans has been involved with the British marquee for nearly two decades.

But why, Hans, did you take a classic sports car and turn it into a …. a hot rod ?
"Well," he replied instantly, "I’m asking myself, wouldn’t the factory put this V12 in the 120 if they had in than ?"
Okay, Herr Professor; it’s a fair cop. Only they didn’t.
In the waning ‘50s, Jaguar was faced with two distasteful alternatives. It could get out of world class road racing, or it could play catch-up with the Ferrari V12. Even while Jaguar was dominating LeMans from 1951 to 1957 with its dohc straight-six 3.8 liter XK engine, the Italians were debugging their V12s.

Not to be outdone by Enzo Ferrari, Jaguar founder Sir William Lyons instructed Claude Baily to create a 60deg, 5.0 liter V12. The racing engine would be followed by a detuned version to power the next generation of Jaguar streetcars. However, while the quad ohc 500hp-aluminum block V12 was still being planned, the Jaguar factory was damaged by fire. Management reckoned they could drop out of racing for a couple of years with no loss. But, somehow, more than tools, documents and chassis vanished in the inferno at Brown’s Lane. The old enthusiasm never returned.
Ironically, Jaguar was out of worldclass road racing. Only now they had a 500hp V12 on their hands.

Following many changes in head and valve layout, the "double-six" had to lose half its cams before it was ready for a production chassis. With 7.8:1 compression, Lucas electronic ignition and four Zenith-Stromberg carbs, the 5343cc motor was good for about 275hp.
It went first into a stretched E-type, the series III. Eventually, the motor found a home in the XJS and the XJ12. Glaser originally bought a basket-case XK120 with the idea of making a roadster companion for his Vintage racer coupe. At the same time, he had made a racing V12 and four-speed from a salvaged XJS. Suddenly taken by the idea that the V12 would fit in the XK120 if it would fit the XKE, Hans grabbed for the chain hoist. Thus was born the Double-Six 120. But it was a long and difficult process.

"It took four years, on and off," Glaser said as we walked around the Double Six. Sleek, liquid and nearly alive, the lowered roadster is finished in high-gloss black with a Dictionary Red Connolly leather interior. Parked among concourse perfect XK120s, it looked like Tina Turner at a meeting of the DAR.
"Getting the engine in wasn’t so bad," Glaser continued, "but everything around it had to be remanufactured. I had to make pedals. The headers go twice through the chassis. There was no room."
He raised the heavily louvered bonnet to expose a lifetime supply of carburetion atop a flawless engine transplant. "We have three radiators: main, and one in each wheel well. And an oil cooler. The motor’s nearly stock – expect for the six Webbers, different cams, higher compression ratio. This version makes 420-odd horses. And it has a lot of torque.
"I’m running the same brakes as on my racecar: Mark IX discs on the front and XK150s in the back because it’s a 150-powerlock rear end. I put Watts linkage and sway bars in the rear and negative camber on the front. Maybe I improved it a little bit, eh ? But it’s not a replicar !"

His Double-Six is a magic cars. Even a short ride in it becomes an adventure. A cute teenage girl leans so far out the window of her boyfriend’s pickup she nearly falls out. Catching herself, she yells "Nice car!" Hans waves to her.

When we accelerate around a quick bend, the blood drains from my eyeballs. I ask Hans how fast she’ll go. Suprisingly, he’s never taken the car over 130mph. But he explains that 4.11 final gearing keeps the speed down. As for mileage, the big Webbers allow 10 of them to gallon. But what miles they are!
Hans has beautifully recreated the tiny, half-round "cheater" windscreens of the racing Jags. The effect is like no glass in front of you at all. At 55 it’s brutal.
Automotive purists may feel about this car the way Glaser does about replicars; they may hate it.

Having seen the Double-Six near other 120s, I can’t fault its appearance. Having ridden in it, I can’t deny its vast, smooth power, though it does get warm around the ankles. And I can’t forget the ride: racey, yet far more stable than the factory XK120/140. It tracked with complete accuracy around corners. When the teenager shouted "Nice car!" she didn’t know how right she was. It is a nice car, for one that’s so bad.