Safe RPM before float
 

On a stock motor, particularly an LQ9. Stock cam, stock spring etc. Now I understand that shift points are determined by where the power falls off, but that's not the question. Just wondering what RPM the stock valvetrain get pushed past the limit. Does FI effect this any?

6k should be fine on stock springs...

Yea, but that's about as high as I would go on the stock equipment...

put a good set of springs on it and the valvetrain will pull higher than the truck intake will go.

my tow haul settings are at 6500, u guys are scaring me, lol

yeah, I was kinda wondering about springs too with the little 4.8. Since it likes to rev out more, I didn't know if better springs and pushrods (weren't LS1 guys having bent pushrod issues at 5k+ rpm?) would be just good insurance.

Boost will make valve float more likely. You should be running out of cam at around 5800 rpm anyways, with your stock cam. Pick out a nice cam & spring kit and put it in. It really wakes things up. Don't forget hardened pushrods.

Yup. Peak HP on the 6.0 is like 5600-5800 tops. So shifting at 6500 with stock cam/springs is definitely a waste and only a matter of time before you drop a valve. They've gotta be floating at those RPM's considering they aren't made for it.
When my 5.3 was stock I had the shift points at 6k. no reason to go over without a cam and springs. IMO

Think the 5800 rpm statement still holds true with a TVS 1900 added to the mix?

On turbo's the bigger concern is exhaust valve float rather than the intake valves. Better springs are important on a supercharger but you should be fine unless you pully down quite a bit.