A motor will not lean pop in every gear unless it is the jetting or a restriction in the fuel supply like the needles and seats or the jets. If it didn't miss before the cam going flat it is probally the valve springs like you suspect The reason I say valve springs is you didn't say which Comp Cam grind you bought, it is very possible that the new cam needs more spring [list] pressure to keep control of the valve train than the old design Mopar cam did It is also possible like some of the other posts say about the ignition, check the plug wires first I have had a motor miss in high gear above 6000 RPMs due to bad spark plug wires