I have a gsr head at my shop w/ aftermarket valves and retainers...dunno about the springs... We got the motor out of a wrecked car and i dont know what they are The kid had skunk 2 cams and intake manifold....so im thinkin there skunk 2....well im tryin to find out the specs on the valves/valvesprings so if any1 has some info id appreciate it....

 

skunk2 valves are black from a nitrid coating and the face of the valve once you clean the carbon off will show a little embossed S2 on it.