Ford Shelby GT500 Convertible: A Summertime Snake in Midwinter Chicago February 8, 2012, 11:39 am Last November, when Ford showed the 2013 Shelby GT500 in Los Angeles, the automaker called the coupe the fastest production Mustang ever produced. Talk of horsepower ratings, track times and live rear axles would have their day in the midwinter sun as well, as Ford released information on the 2013 Shelby GT500 convertible ahead of its debut at the Chicago auto show, where press previews are taking place Wednesday and Thursday. Befitting all Shelby-branded Mustangs, the convertible's equine bones are hiding in plain sight. The telltale cobra supplants any nominal signs of the horse, including on the car's grille, where the badge migrates from on-center to the left. Other clues to the car's provenance include a recessed hood scoop, larger wheels and brakes, white racing stripes and quad exhaust pipes. Aside from confirming the presence of the supercharged 5.8-liter V-8 engine found in the GT500 coupe, generating 650 horsepower and 600 pound-feet of torque, Ford did not disclose performance estimates for the convertible, saying only that it would be the fastest production Mustang convertible offered by the company, and noting its superior lap time around Sebring International Raceway to that of the previous GT500 convertible. That car was priced at $54,605. Pricing for the 2013 car was not announced. The new convertible will compete against the topless Chevrolet Camaro ZL1, unveiled last November at the Los Angeles auto show. An advantage claimed by Ford in Los Angeles was the Shelby coupe's avoidance of the gas-guzzler tax. A buyer of the ZL1 hardtop could expect to pay a penalty of roughly $1,300 above the $54,995 base price, according to Car and Driver. Ford is also using the occasion of the convertible's debut to note the 20th anniversary of its Special Vehicle Team in-house performance unit. The convertible includes a commemorative lighted door-sill plate to mark the occasion. SVT received little attention from Ford during the "00s until the F-150 SVT Raptor gave it a muddy makeover in 2008.