at what RPM do the valves start floating with stock valve springs? thanks.

 

wit boost 5kish

without 6500ish

 

excellent, thank you

 

what RPM will a stock motor hold safely? i have bolt ons only

 

6100K without Rod Bolts
6500K With Rod Bolts

 

I have no real world experience with this. Some members on this site said they can spin 6200 RPM's on a stock bottom end 5.3 with no problems. They hit these RPM's quite often too. I'm pretty sure bluecajun5.3 said this before.

 

valves can float at an earlier rpm as well. dpends on mileage and etc

as for what rpms. its reasurance but ppl including myself have rev'd a motor 7k without issues for periods of time

 

I turned my truck to 6200rpms on the 5.3 with bolt ons only for a good while.
With my 6.0l with 918springs i turn it to 6700rpms no problem.
Maybe with the new heads i'll be able to turn a little more...

 

I ran a stock 5.3 (with rod bolts) up to 7k on a regular basis. It wasn't the bottom end that was the problem. It was a wrist pin in my case.

With the right springs, intake and cam, I would do it again without question.

 

would a set of z06 springs be a wise investment?