Tore it down today. Timing ok, rockers ok. Put the stock pushrods back in. No change. Tore it down a second time and put the stock cam , and springs back in. Runs fine. Guess a tune would have fixed the problem. Oh well . Guess I'll have some things for sale !!

 

man thats a lot of work for nothing.6.0 is the way to go

 

Tell me about it !!

 

Sorry to hear that!
I just bought the same cam and springs. I hope I'll be OK. How come you did not try tuning? I believe you have a 6.0L is that correct?

 

Correction. I just read the whole thread, you have a 5.3.

 

Its a bit much for a heavy truck and a 5.3,tuning would have helped.On mine I had the ideal raised 75RPM and drilled the hole slightly.I am a believer in LS6 springs.

 

Didnt want to spend any more money on this thing. Only wish I had a 6.0 now.