Wondering what the stock rpm's are on the 12 valves. I notice on mine the tachs redline starts at 3k and if this is the case wouldn't putting in a 3k or 4k spring kit take a chance on engine damage, or do I misunderstand and the spring kits are for something other than increasing rpm's. Last thing is how can you tell if a kit has been previously installed?

 

Stock springs in your pump start defueling at 2200 rpm and sign off completely at 2500 rpm.......3000 rpm GSK will start defueling around 2700 rpm and finish around 3000 rpm depending on how they are adjusted.........your truck will pull hard past 2500 rpm if you have a GSK installed..........4000 rpm kits require an exhaust valve spring swap in addition to the GSK..........Not certain but I have been told that damaging harmonic vibrations occur around the 4200 rpm mark - I don't know if this could be changed with a different balancing technique or a custom damper.

 

all tachs in dodges are the same. they all show "redline" at 3,000 rpm. i have seen cummins go past 4 and hit the bottom of the guage and sit there many many times. nover for very long of course, but it will do it. there is no need to go to or past 4 because its way out of the power band anyways. if you get the governor springs, then just ignore the redline marks and imagine that they start at 4-k when you are racing a ricer and then imagine them moving back to where they are really when just cruising. you will find that if you do get the 4-k, you will never have a need to go past 3500 even when full-out racing. to figure out the stock max rpm's you'r motor runs, just mash the throttle to the floor and see where it stops. if it goes past 3,500, then you should promptly let off because it alredy has governor springs. you won't hurt the engine just running at governed speed for a few seconds.

 

Okay on my way to work this morning I put the truck under full throttle till the tach stopped climbing. It stopped right on the 3000 line, haven't tried wide open in park or neutral yet. Would you say it probably has had a 3k kit installed. I did this with OD turned off so I could reach the limit without reaching top end speed.

 

it would be safe to say that it has 3,000 gov springs already. if the motor sounded like it was freewheeling and not making any more power, then you have 3-k. it will do the same if you put it in park and floor it. so no need to try it.

 

Yeah, on a 95 with a little more fuel added (stock plate forward), if it will still hit 3000 RPM under load (going down the road), then it probably has had some governor work.

Mine would barely hit 26-2700 under load, and would start dropping boost (and therefore fuel) at around 23-2400.

Either that, or you've got one heck of a good running truck
Chris

 

I just put the 3GSK in my Dad's 96-Prior to the install the truck would run to about 2800, now it rips right past 33-3400. Some "experts" around here have said that they spoke with Cummins and the stock 12 Valve valve spring is good to 3600 RPM, I verified that with Piers.

 

A stocker will slowly make it's way up to 3000 rpm in 3rd without a GSK but at what rpm did it stop pulling hard and making power?

 

The truck zipped right up to 3000 rpms in just a matter of a few seconds and felt like the power didn't start to decrease until just before or right at the 3k mark. I'll have to try it again on the way home and pay a little more attention on how it does this time.

 

Well, if it pulls hard right up to 3000 rpm it would be safe to say that you probably have a 3000 rpm GSK ...........

 

Has the safety (tamper proof) wire been cut or removed that goes in front of the access port to the springs? If it has or has been removed pretty good bet it has been at least worked on.

 

There are some trucks that come from the factory that are different. My friend bought a truck off a guy that we have known for years infact we went with him to pick up the 96 Dodge when he bought it new. He or my friend have never touched the truck and it will flat rev to 35-3600 rpms all the safty wires and break off screws are still in place.
and thats not the only truck that I know of that is stock and will pull far past redline.
DM01

 

My 97 will rev to exactly 3 k rpm in 5th gear and doesn't take long getting there, never tried it in any other gears , tried it in neutral one day , and i let off when it got to 3250 rpms , it was still climbing , never really checked the lock wire , will do that some day when it warms up a little , but the AFC housing still has the tamper proof screw in it.

 

mine was stone stock, ran to 3k in 4 or 5th[started defueling at 2650]. it would free rev to 3500 in neutral with the pedal on the floor. 97 215 pump