I have noticed that many later model stock heads use valve springs with no dampener coil inside. Back in the day just about EVERYTHING had that little flat coil inside. Why did they need it back then but they don't feel it's necessary nowadays?

I generally don't have the time to play extensive valve spring games with my motors so I install the springs the cam manufacturer recommends at correct installed height regardless of whether they have a dampener coil or not. What if you were to leave it out of a spring that came with one? Would all heck break loose in the higher RPMs?

 

The damper was just that, something to try to control the sometimes wild motion of valve springs as the engine revs thru it's range.

Modern analysis equipment like the Spintron let folks test spring and valvetrain components to determine what works. In most(?) cases they have been able to eliminate the damper. IMO, the constant rubbing of the damper on the springs not only wore them, but it generated lots of extra heat which isn't good. Dual springs sometimes purposely rub on each other to achieve some damping. I personally like the beehive springs which are somewhat self-damping because the different diameter coils have different resonant frequencies.

You idea of following the cam manufacturer's (or your valvetrain designer's) recommendations is a very good one. That makes a lot more sense than second guessing the pros. The old saw, "When in doubt, leave it out!" applies to using a comma in a phrase, but not to valve train components.