In December 1966, Chevrolet then quietly released one of the most famous options codes of all time, option Z-28. Unpublicized and unknown by most of the buying public (and most Chevrolet sales people for that matter) and not mentioned in any sales literature, the only way someone could order the Z-28 package was to order a base Camaro with the Z-28 option, mandatory front disc brakes with power assist, and the Muncie 4-speed transmission. You could not order the SS package, automatic transmission, air conditioning, or the convertible. What you got was a unique 302 cid small block (Non-California emission cars were labeled MO while California emission engines were labeled MP) that was created by taking the 327 block and installing the short-stroke 283 crank. Specifically designed to compete in the Club of America Trans Am racing series which placed a 305 cid limit on its entries, the Z-28 was available to the public solely to qualify the car for racing. Advertised horsepower was listed at just 290bhp, which was not very impressive until one hooked it up to a dyno and got actual readings of 360-400 bhp. The Z-28 also came with a competition suspension, broad racing stripes on the hood and trunklid and could be combined with the RS option package. There was no Z-28 badging at all, lest it attract to much attention. The Z-28 proved to be difficult to launch on the street because its high reving engine was lethargic under 4000rpm and worked best when it was shifted at 7500rpm (!). Once it got going, the Z28 was tough to beat and boosted a 140mph top speed and numerous racing victories. Only 602 Z-28s were sold in 1967, making it a truly desirable collectable.