Think it's time for new Valve springs..
 

Well, I pulled 2 springs off the heads today as I am going through the valve train before and after the new cam goes in. I'm guessing there are about 15k miles on the heads/springs as I bought them used from a buddy and taking a guess on my mileage as I do not have an odometer in the truck.

They are Crane 832's and I am running a Trex cam.
The two springs I check come out at:

Spring 1
1.80 = 80lbs
1.15 = 311lbs

Spring 2
1.8 = 75lbs
1.15 = 300lbs

Spring pressure should be according to Crane's web page
1.8 = 112lbs
1.15 = 352lbs

Didn't have any valve float, but the dyno graph fell of pretty quick at 7,100. Wonder if the springs were holding it back a little..

Dyno pic should be working soon:
http://73-ls1.com/63truck/Dynos/Supervic_LS6.jpg