General Motors Vice Chairman Bob Lutz is retiring May 1 after 10 years, following notable careers at Chrysler, Ford and BMW.

His achievements already have been chronicled by Ward’s and thousands of other publications, but GM’s vehicle interiors owe him a special debt of gratitude.

Auto makers have been paying lip-service to the importance of vehicle interiors for years, but only recently have most high-volume producers started putting money where their mouths are, and GM is a prime example.

Four years ago, GM had some of the industry’s most mediocre interiors in quality and overall design. Lutz bemoaned their state during a keynote address at the 2006 Ward’s Auto Interiors show.

“The last happy hunting ground where a vehicle line executive could claw back the cost is the interior,” Lutz said back then.

Interior design was such an afterthought in GM culture then that it took a while to convince a company executive he was being promoted, not demoted, when he was moved to an interior design leadership slot, he said.

Lutz made it clear in 2006 he was going to force a major change in attitude, because the vehicle’s interior, “is the last place in the world where you want to advertise the cheapness of your product,” he said.

He even warned suppliers about overusing mold release agents to speed up production of plastic parts because it could cause an ugly sheen.

Today we are seeing the fruits of those labors in every new product rolling out of GM’s design studios. The elegant Chevrolet Equinox won a 2010 Ward’s Interior of the Year award in the popular-priced truck segment and the nostalgic man-cave interior of the Camaro took honors in the sports-car category.

Each vehicle not only features a high-quality, highly crafted look, but also a sense of style that has been lacking in most of GM’s vehicle interiors for decades.

GM designers turned to the first-generation ’67 Camaro, when the interior was most distinctive, for design inspiration for the newest version of the car.

Even though stylists picked up that generation’s design cues, such as a console-mounted gauge package, they still gave it a modern interpretation, one that meshes with the new Camaro’s exterior, which also is a fresh reading of a classic shape.

Creating design harmony between the interior and exterior is another promise Lutz made four years ago.

Now the strategy is paying dividends. The Equinox and Camaro are selling faster than GM’s factories can build them. Transaction prices and profit margins are the best the auto maker has seen in recent history.

Of course, these vehicles are not flying out of showrooms only because of their interiors. They also have superb exterior design, great engines, and impressive fuel economy.

But, improving powertrains and exterior design historically have been easier causes to champion, leaving interiors to die the death of a thousand cuts from the budget axe.

But Lutz pointed out in 2006 that the interior can make or break a sale, and he did not shrink from his mission. And GM interiors now clearly are making a lot more sales than they are breaking.