Verne, the SCCA said that Chevrolet had to install the option on at least 500 cars to make it legal for Trans Am racing. And Chevrolet showed them that the option was being ordered(Chev probably installed it themself on cars to run up the numbers) so it was a legal option. But in the end, there were only 206 cars built with the JL8 option. Most of the racers used the HD service package rear since it was much cheaper than the full JL8 option. The ZL2 cowl induction hood was another option that they needed to produce a minimum 500 units to make it legal. Racers were using the fiberglass crossram hood(estimate of around 100 made) but the ZL2 option was a steel single 4 bbl hood which made the fiberglass one eligible as well. In Wayne Guinn's book he describes how the JL8 rears were built by modifying standard 12 bolt rears. They were done in batches which also made availability limited. When you look back at it now, 4 wheel disc brakes on a 1969 Camaro is pretty awesome considering the only other cars to have it were the Corvette or some exotic exports. But it's not just that it's 4 wheel disc brakes, the setup was created and tested to allow for serious road racing and could handle an incredible amount of braking during a race without heating up too much and fading out over time. Most new cars with 4 wheel discs have tiny rear rotor which would never be able to handle the rigors of racing.
