1969 Camaro Smog System Question

[Unreal]

Rick,
I know that's why they used the over valve cover one on A/C cars. My point was that if they used the A/C type one on a solid lifter car, they would need to remove the check valve every time they adjusted the valves. It doesn't make sense that GM would use the over cover unit when they had an alternative already in the parts bin that would not require disassembly to adjust the valves.