12valve

like the title says, how many rpms can be run on a 24 with stock valve springs? its got a p-pump

just deciding wheather to put in 3k or 4k GSK.

busa

Would like to know the magical number before valve float as well

sledcrusher02

its just not a magical number other things factor in such as drive pressure but i would venture to say above 3200-3500 your playing with fire.

BigB82789

The redline. Thats why it's on the tach.

Big Blue24

Redline has to have a little fudge room. What is it anyway, 3200? I have revved mine to 3400 or so with no load when I lift late on a shift. My motor should have tired springs with 232,000 and a lot of that dragging a trailer. No problems here.

cyric

I have floated my valves at 3700 on my truck, but that is also pushing 55-60 psi boost. What a hideous sound it makes. F1 sportsmans springs are my next mod. I think it varies with drive pressure and boost. I know not much help.
Joe

19Fury69

my trucks hit 3800ish when the tranny decided to kick down or pop out of gear at the higher end of 2nd after a light, almost needed to change shorts after that one, I think its defenitly time for a new tranny haha.

Tate

I've had mine to 3500 a couple times, but don't do that too often. I'd say get the 4k kit, and then you can pull the small springs out if you want. I've got 3k GSK in mine currently, and it has plenty of revs. Thats on a 215 pump, depends which one your friend is running.

12valve

thanks a lot.

its a 215,
ordered the 4k, just wanted to know for sure, wheather to install the small springs or not.

truck makes no more then 40 psi boost

thanks!

HOHN

I've zipped my truck higher than I wanted to a couple time by being late to shift-- and it's kissed 3800 or so.

But! This was happening in low gears--meaning low speed and low boost. I do NOT regularly do this, nor would I advise it, even at almost no load.

I do remember the TSB for "bent push tubes" or something that has a Cummins recommendation to hold the engine at 3500rpm or something really high like that for a full minute!

That tells me that Cummins thinks 3500rpm is safe at no load, anyway.

EDIT: TSB link here.

JH