The rivalry between the Chevrolet Camaro and Ford Mustang is always intense, and these two vehicles have traded sales dominance back and forth countless times throughout their 30-plus year history.

Recently, the relationship between these two famous models has shifted yet again, as the Camaro has been trouncing the Mustang in sales. This is a complete reversal from just a year ago, when it was the Mustang on top.

Sales totals for May show 9,451 units sold for Chevrolet, with Ford managing to move just 6,607 Mustangs. That's a big drop-off for Ford, which sold 10,225 Mustangs during the same month in 2010 – when Chevy was only able to sell 8,931 Camaros.

Still, Ford is quick to point out that the Mustang is not knocked out yet, and that high gas prices made May an unattractive month to buy a muscle car.

"Although May (Mustang) sales were down, calendar year-to-date sales were only down 2.8 percent," Ford spokesman Octavio Navarro told Edmunds Inside Line. "Our focus, in combination with our other cars, is to continue to grow our car market share."

Drivers interested in a used Chevrolet Camaro or Ford Mustang would do well to check out New Jersey State Auto Auction, which offers both of these cars for sale.