The AC stands for Auto Carriers Ltd. is a British specialist automobile manufacturer and one of the oldest independent car marques founded in Britain.
I found this at Wikipedia:
The first automobile from what would eventually become AC was presented at the Crystal Palace motor show in 1903; it was a 20HP touring car and was displayed under the Weller name. The Weller Brothers of West Norwood, London, planned to produce an advanced 20 hp car. However, Portwine (their financial backer) thought the car would be too expensive to produce and encouraged Weller to design and produce a little delivery three wheeler. Weller did so, called it the Auto-Carrier, and a new company was founded and named Autocars and Accessories; production started in 1904. The vehicle caught on quickly and was a financial success. In 1907 a passenger version appeared, called the A.C. Sociable. It had a seat in place of the cargo box.
The company became Auto Carriers Ltd in 1911 and moved to Ferry Works, Thames Ditton, Surrey - at this time they also began using the famed "AC" roundel logo. Their first four-wheeled car was produced in 1913; it was a sporty little two seater with a gearbox on the rear axle. Only a few were built before production was interrupted by the first World War.
And check out the grill shape on this one, it looked more like Aston Martin and Maserati got together: http://upload.wikimedia.org/wikipedi...ports_195_.jpg
This is the AC Ace http://upload.wikimedia.org/wikipedi...e-archives.jpg
It is the car that Carol Shelby put the 289 in but I like it best of all because the fender wells haven't been modifide. The car was actually considered under powered but with the 289 it became a world class sports car and we all know what it turned out to be with the big block. An absolute MONSTER!