(click image for larger view) Neil Young's 1959 'Thinkin Lincoln'

When do you try to convert one of the behemoths of the tail-fin era into a model of automobile fuel efficiency?

Ah, when you're pop star Neil Young with a spare $120,000 for a little detailing -- details like a UMQ Technologies electric engine that replaces the gas hogging V-8 and a rare rotary engine running on compressed natural gas that takes over when the batteries run out of juice. In addition to driving the car, the rotary drives a generator that recharges the batteries.

Young has equipped the nearly 20-foot long 1959 Lincoln with electronics that capture its operational data, display it on a screen below the dash, and transmit it to the Internet. He stopped by Salesforce.com's user group meeting in San Francisco yesterday to talk about his beloved, 5,000-pound convertible, one of several vintage cars he owns, to describe how he's trying to convert it into a model of ingenuity and efficiency.

The goal is to get 100 miles to the gallon; Young says he's already halfway there.

After listening to a description of the car, Salesforce CEO Marc Benioff told him his fan base will be eager to check the www.lincvolt.com Web site to track his whereabouts in real time. Young hastily injected, "There's been a little delay built in."

When enroute someplace, Young doesn't like stopping his "Thinkin Lincoln" to refuel, which is a good thing, because there are few service stations in the U.S. where you can fill up your compressed natural gas tank. So a long driving range between refueling stops is a secondary goal.

Young carried on a lively discussion on the car with Benioff for several minutes, then the cream-colored car with tan top itself was driven onstage, its hubcaps looking like slowing turning turkey platters. It was driven by the Wichita, Kansas, car shop owner, Jonathan Goodwin, who is rebuilding it as an energy efficient vehicle.

Young believes that car owners should recharge their cars at home, taking service stations out of the picture and replacing them with the nation's electric grid. Natural gas is a good fuel as well, he believes, because there's a lot of it that can be recovered in the U.S.

The car cruises at 80 mph on its electric motor but is capable of doing 160, Goodwin said. It will run for 80-100 miles on the batteries, then need to recharge.

He said he'd rather convert the Lincoln, which is "a piece of American art," than buy a Toyota Prius. The Lincoln's tan soft-top was in the process of gently folding itself into a compartment behind the rear window.

"That's American ingenuity. That's innovation. You've built something spectacular," gushed Benioff.