Bold, powerful, unforgettable. That's the image that both the Camaro and the Mustang represent. Knowing the historic rivalry of these two iconic muscle cars is as essential to car enthusiasts, as knowing how to brew coffee is for employees at Starbucks. To car enthusiasts who happen to be investors, like me, it means just that much more. I mean no disrespect to the third auto manufacturer in Detroit, Chrysler, but when I think about the in state rivalry, it's all about Ford (F 0.66%) and General Motors (GM -0.17%). Between those two, Ford's been the bully lately, touting the top-selling vehicle and truck in the U.S. market and also stealing the Silverado's buzz at the recent 2013 NAIAS show with the Atlas concept. GM isn't going to sit there idly: Here are two recent punches thrown back at its Detroit rival.

Camaro races ahead
This pains me to say, as an auto investor that happens to love his 2010 Mustang GT, but I must give credit where credit is due. The recently remodeled Camaro is one awesome looking ride, and consumers agree -- the Camaro has topped the Mustang for three straight years in U.S. unit sales.

The trend lines are improving for both, which should bode well for their sales and brand image, as the overall market improves. We'll see if these two muscle car juggernauts battle it out for sales like in the '70s and '80s, but for now Camaro has the edge. However, before you get too worked up, during the 42 years when both models were produced, the Mustang has won the sales title 31 times to the Camaro's 11. These two vehicles mean a lot to their respective company's image, but today it's more of a pride issue as the Mustang ranks 8th in sales for Ford's brand in the U.S. and Camaro is 7th for Chevrolet. We know where the battle line is drawn: the Sierra and Silverado versus the F-Series. Adam Jonas, an analyst at Morgan Stanley, estimated that the F-Series accounts for an estimated 90% of Ford's profit globally. For GM, the story is similar, as the Silverado and Sierra together equal roughly 60% of GM's profit globally. Sorry iconic muscle cars, time for you to take the backseat in this brawl.

GM fights fuel efficiency
Recently Ford has been stealing some buzz from GM by showing off its fuel-efficient EcoBoost engines in its commercials. Consumers have responded since 2007, when the Silverado and F-150 were neck and neck in market share, and Ford held 16.5% share versus Chevy's 16.1%. Three months ago the F-150's share surged to 22.8% while the Silverado's slipped to 16%. To see how important fuel efficiency is, compared to other factors, simply look at the graph from KPMG below:

Source: KPMG. Automotive investors should take a look at the full report (link opens PDF) from KPMG.

Ford isn't alone with the fuel-efficient advertising, Chrysler is touting the Ram's best-in-class 25 mpg on the highway. Time for GM to punch back, and it's doing so with recent advertising. "We just started a campaign on Chevy trucks where we have lowest total cost of ownership ... That includes operating costs. Inside of that is maintenance and real-world fuel economy," said GM North America President Mark Reuss.

I think this is a tactic that could pay off for GM if it's executed well. Reminding consumers that more goes into saving money than just at the pump. It just so happens there is a perfect medium for these advertisements, the upcoming Superbowl. It appears GM opted not to pay the high price for ads during the actual game, but has four ads during the pre-game show. I'll be shocked if that message isn't part of the Silverado's ad.

Bottom line
The rivalry between Ford and GM is about to heat up significantly. GM is planning to roll out redesigns of the Chevy Silverado, Chevy Impala, and GMC Sierra. By late summer, a new Chevy Corvette is slated to release, followed by the Buick Encore crossover by February 2014. The Suburban, Tahoe, Yukon, and Escalade are expected by the first half of 2014. Ford is at least slightly worried, or it wouldn't have shown the Atlas concept at the 2013 NAIAS show to entice potential buyers to wait a year for its truck.

I think these two will be battling for market share and profits, among many other competitors, in the surging U.S. market. As auto investors, I think it might be time we look at both these companies as viable investments, and hope that the lessons learned in the recession keep them profitable into the distant future.