Valve springs
 

I see the preference is dual. I understand dual has a built in safety with the second spring. However beehives seem to be highly regarded in many other performance apps. Anyone have real world experience? I'm at the point of picking springs and wanna get it right.

Here is a speedtalk thread where they are highly regarded. Some breakage mentioned generally from the wrong spring for the application also a mention of a certain issue that was repaired in the springs themselves.

http://www.speedtalk.com/forum/viewt...t=1102&start=0

Here's a super chevy article explaining how the harmonics and stability are better with the beehives.

http://www.superchevy.com/how-to/eng...ind-the-coils/

Personally I don't see them being durable enough for endurance application... I have them in my Cobra, but for that it's fine, constant rpm over 5000+ I would not use them.