There's broken PRC duals as well. Just go read on Tech.

 

But atleast with a dual spring there is less of a chance of dropping a valve...

 

This is what I've been seeing, there have been numerous threads both here and on tech with pics of broken silver 918's...I'm going to use PAC 1218's with my future setup.

 

Go with the 1518s. They're only $50 more than the 1218s. Im kicking myself now for going with the 1218s and not the 1518s and have to deal with a spring change now. Most cams nowadays are at or have more than .600" lift.

 

Nope, no need for them, the cam I'm planning on is the TrickFlow 220/224 .575/.575 112, so the 1218's will be more than adequate. I'm not going to put unnecessary stress on my valvetrain and have to worry about pre-mature lifter failure because my valve springs have so much seat pressure that they're blowing the lifters out. If I ever decide to get a bigger bumpstick I'll upgrade the springs at that time...the Crane valve spring tool makes it a piece of cake

 

I run lunati gold .660 springs for $200.. btw dozerdan broke a 918 with a .600 cam and got alot of **** for it..