How do I set valve lash?

74 Plymouth valiant, 198 slant 6. Not sure if I set the valve lash correctly. My buddy told me to crank the engine over till the intake and exhaust lifters lift and fall then they become parralell. Then use the measurements of .012 for intake and .028 for the exhaust. Let me know what you think, please and thank you.:swinging:
Author: Mrpyro187