Quoting "Woolf,Richard" <richard.woolf@xxxxxxxxxxxx>: > Is all this octane booster really necessary? I do not believe it is necessary. Both my 68s have 10.1:1 compression ratio, and they are both happy with 92/93. In fact, both are advanced more than the stock specs. The taller cams actually help tolerate the lower octane. In a stock cam car, the peak pressures and temperatures occur at relatively low rpm when the turbulance is not very high yet. With a bigger cam, the peak torque (and therefore peak cylinder pressures and temperatures) occur at higher rpm, where the higher degree of turbulance speeds up flame propagation within the cycle and reduces the knocking tendencies. When I first got my LeBaron though, it did suffer from knock even with premioum, but that was mainly due to carbon build up. After I drove it a bit hard, it cleared up. D^2