Mustang and Camaro in lean muscle car fight

NEW YORK (CNNMoney.com) -- For a few days, Ford could boast of having the most powerful V6 in the segment with its 305 horsepower Mustang engine. But then General Motors revealed that the 304 horsepower rating on its Camaro V6 wasn't actually official. The official rating, it turned out, was 312.

Gotcha, Ford!

Wait, are these Detroit automakers really trading jabs like junior high boys over horsepower ratings on fuel efficient V6 cars? Used to be they did that only over their high performance V8 muscle cars, but the times -- and the technology -- have changed.

Relatively fuel efficient V6 engines have always been popular on these so-called Pony Cars, but they were mostly sold as cheap-to-own alternatives that looked like their high-performance relatives while driving more like family sedans. Auto industry types referred to them dismissively as "secretary's cars."

But today's V6 engines have become serious performance contenders in their own right. Plus, there's now a new generation of buyers that doesn't equate performance with massive engine blocks.

"You look at 'millenials' and they're much less concerned with V8 horsepower," said Eddie Alterman, editor-in-chief of Car and Driver magazine, speaking of young people who came of age after the year 2000. "Much less so than their fathers are."

Mustang and Camaro buyers can still get more power -- much more -- by opting for the V8 engines in the new Mustang GT and Camaro SS. Still, the power in the V6 cars is now more than adequate to send up respectable clouds of tire smoke.

The Mustang V6's 305 is just 10 horsepower less than the 2010 model year's V8 engine. Although the gap in torque -- the type of power used for acceleration -- is larger, there's still plenty of power for fun driving, Alterman said.

"The younger generation are happy with the V6 and financial reasons are important too," said Mike Omotoso, an industry analyst with J.D. Power and Associates.

V6 cars just cost less. There's a roughly $7,500 difference between the base sticker price of a V6 vs. a V8 mustang. Beyond that, there are substantial differences in fuel and in insurance costs.

Despite quickly having its horsepower crown snatched back by Camaro, the Ford Mustang V6 still claims bragging rights as the only car to offer over 300 horsepower while getting more than 30 miles per gallon on the highway. (True only with the optional automatic transmission.)

"The new Mustang getting 31 mpg is a partial selling point," said Omotoso "but the main selling point is still the 305 horsepower."

It seems like the attraction of those more powerful V6 is making a difference in sales.

The test case is Chrysler Group's Dodge Challenger. There, the V6 "secretary car" stigma still exists. With the base V6 , power output is limited to just 250 horsepower. If you want genuine performance in the Challenger, your only option is the 370 horsepower V8.

Consequently, 65% of Challengers are sold with the V8 engine, compared to a nearly 50/50 split for the Mustang and Camaro, said Omotoso. Chrysler confirmed Omotoso's figures.

Chrysler begs to differ as to why. The real reason, a Chrysler spokesperson said, is that Challenger's V8 engine is stamped with that heavily marketed Hemi name. And Challenger buyers just have to have a Hemi.

For now, at least, the most performance-oriented car shoppers don't seem to be hearing the automakers' claims.

A detailed analysis of Internet "chatter" -- blog postings and comments -- done by J.D. Power and Associates for CNNMoney.com shows that, while muscle car fans are talking about V6 performance, they're not saying they'd prefer to buy it over the good old V8.

"For the real 'muscle car lovers' --the V8 seems to be the only choice," J.D. Power said in the report. "In fact, the small amount of discussions indicate that the brands (Mustang and Camaro) may lose credibility when they continue to push the V6 performance messages of the vehicles to muscle car lovers."

Not everyone, it seems, is ready to hear the "smaller is better" message.