In order to run the ZR1 cam a different 3bolt cam sprocket is needed. On the LM7 the cam sensor reads off a reluctor wheel built on the camshaft. The ZR1 reads off a reluctor on the cam sprocket with the sensor on the timing cover. The new cover and sensor were only $75. The timing set I was going to replace anyway was the same cost as the LM7. GM parts are ridiculously cheap.