Hot rodding isn’t just about greasers in 1950s or ’60s cars anymore. And neither is the hobby’s iconic handbook: Hot Rod magazine.

The glossy monthly magazine, which operates from an El Segundo office, will have about 50 percent more pages beginning with the September issue, which goes on newsstands this week.

It’s a rare track to take in the print publishing industry, in which many periodicals are cutting back. But the magazine’s publisher, Source Interlink Media of Bonita Springs, Fla., is pushing down the accelerator on a bet that the magazine can draft off the popularity of new cars with classic body styles, such as the Chevrolet Camaro, Dodge Challenger and Ford Mustang.

“What they’re doing in Detroit – it’s like the muscle car wars of the ’60s coming back,” said Doug Evans, senior vice president at Source Interlink. “It takes you back to the heyday of the mid- to late ’60s when the whole thing was really, really catching on fire.”

The September issue weighs in at 180 pages, compared with 122 pages the prior month. About 40 new pages each month will be editorial, including about 15 pages devoted to new cars.

The expansion reflects an upfront investment of about $1 million from Source Interlink, which plans to spend more in the future to sustain the larger product. Three staffers were hired as part of the relaunch. The magazine now has five full-time editors, up from two full time and a third part-timer a few years ago.

The magazine is the publishing company’s largest and most prominent title in a group of 21 magazines for performance car enthusiasts. Other titles take a more specialized focus, such as Camaro Performers.

Many of Hot Rod’s readers use the magazine to get ideas for their own customizations, which can range from putting on high-performance tires to supercharging their engine or simply putting on new valve covers. And the magazine’s expansion is partly based on a growing aftermarket for the new muscle cars. That means more advertisements and more products to feature on editorial pages.

Still, much of the magazine’s coverage centers on classic cars. The average print reader is male and in his 40s. Publisher Jerry Pitt said he’s hoping that by featuring new cars, and promoting more stories using social media, the magazine will be able to add readers who may be just a few years out of college.

Judging from the turnout at car shows in the area, Marlon Mitchell, president and founder of San Fernando Valley car club All Mustang & Ford Club of Southern California, said expanding that way makes sense. He has seen an influx of customized late-model cars at his monthly meetings and at other events, where they sometimes outnumber the classics.

“They’re trying to reach a wider base,” he said of Hot Rod magazine. “There’s a big craze in buying a new car and jamming (20-inch rims) on it and a new exhaust. A lot of people are buying these cars and want to know what to do to them.”

Slowing down

Hot Rod, which has a circulation of about 650,000, of which more than 600,000 are subscribers, can trace its beginnings to the explosion of souped-up cars in post-World War II boom times. The magazine launched in 1948 as GIs came back from the war and began to fix up their rides.

The hot rod culture then was focused on speed, and much of the early racing action happened in the dried-out lakes and closed-down airstrips of Southern California. Though the hobbyists were once thought of as outlaws, they gained mainstream acceptance by way of Hollywood movies such as “American Graffiti” and by being featured in the pages of Hot Rod.

The magazine started as the passion project of the late enthusiast Robert E. Petersen, who founded the Petersen Automotive Museum on the Miracle Mile. But the magazine has been bought and sold numerous times since: most recently purchased by Source Interlink in 2007. The company once counted Ron Burkle’s Yucaipa Cos. as a main investor. It went through bankruptcy reorganization in 2009 and is now privately held. The company has a specific focus on automotive magazines and publishes the popular Motor Trend. Another division publishes magazines about customized foreign cars, called tuners, which were featured in the “Fast and Furious” movie series.

Though Pitt said his magazine hasn’t lost substantial market share to the tuner titles, Hot Rod’s size has fluctuated under different ownerships over the years. It began to particularly languish in the latter part of last year, when some issues came in around 100 pages. That’s when he realized the need to reinvest, convening with Evans and Hot Rod Editor in Chief David Freiburger to stage the current relaunch campaign. The magazine had a 19.1 percent decrease in advertising pages during the first quarter of this year compared with last, according to a report from magazine trade association Publishers Information Bureau.

“We were downsizing into oblivion. It became apparent that for us to have a strong digital (presence), we needed to lead with the print magazine,” Pitt said.

Of the magazine’s roughly $20 million in annual revenue, more than 50 percent still comes from the print edition. The idea with the relaunch is to recoup some of the investment from additional advertisements and subscriptions.

In fact, the new magazine will have about a dozen pages of more advertising. Much will come from existing advertisers who were given deals to expand their ad buys, although Pitt said he’s bringing in some newer ones, too.

Some ads are clearly tied to the expanding new-car content, such as a prominent fold-out advertisement for Hanover, Germany, tire maker Continental AG. The ad, which spans three pages, showcases the company’s tires on a yellow 2012 Chevrolet Camaro ZL1 – the same model that Freiburger drove more than 200 miles an hour for a feature in the magazine.

The magazine has made readers aware of the relaunch campaign in part through last month’s Hot Rod Power Tour, a seven-stop car show that visited locations around the country such as the Buffalo Run Casino in Miami, Okla.

Revving up

By reinforcing the print product, Hot Rod is also hoping to increase the value of its other properties, such as the “Hot Rod TV” show produced for cable channel Speed TV and videos produced for YouTube.

Underpinning the YouTube effort is the goal of drawing younger digital age audiences into the print fold. The strategy is on display in the September issue. Two of the biggest stories were teased weeks before publication with online videos. One is based on the magazine’s cover story, which compares the 2012 Lamborghini Aventador LP700-4 and a fixed-up early 1930s Ford Model A for how much attention they can grab around Los Angeles in locations such as Hermosa Beach. The other story features Freiburger’s successful attempt to take that Camaro beyond 200 miles an hour on a closed course. The videos were viewed about 600,000 and 150,000 times, respectively, on YouTube by July 3, a week before the magazine hit newsstands.

Freiburger said the stunts and stories indicate a renewed editorial effort to wow readers in the age of digitally shortened attention spans.

“Every issue, I need to have a story or two where people say, ‘I can’t believe they did that,” he said. “We have some fairly insane things, some wild things.”

The strategy is helped by the new retro-styled muscle cars. But how long will Detroit continue making them?

Despite the enthusiasm of their owners, the muscle cars represent a relatively small portion of new-car sales. For example, the new Dodge Challenger had its best June sales on record last month, when 4,000 of the vehicles were sold. Still, that’s less than 3 percent of Dodge’s parent Chrysler Group’s total new-car and truck sales of 145,000 during the month. And it’s less than 20 percent of the sales of Chrysler’s top seller, the Ram pickup.

What’s more, some throwback vehicles have already shown they have a limited shelf life. Chrysler’s PT Cruiser ceased production after the 2010 model year after an 11-year run, and Ford’s Thunderbird made a four-year comeback that ended with the 2005 model.

Ceasing production of the new hot rods may not ultimately hurt the magazine a great deal, given the hobby’s penchant for older models. Still, there’s no doubt that their resurgence has been good for Hot Rod.

Some speculate that the cars in their current state will face too many hurdles from stricter emissions standards. Others point to press reports of Ford Motor Co. abandoning its retro Mustang with the 2015 model and make it look similar to its sleek, futuristic Evos concept car.

But if Detroit were to announce the intention to drop the new muscle cars, it could backfire, said car club founder Mitchell.

“They’re going to get a lot of feedback not to do that,” he said.