I was thinking of geting 3k gsk with my #6 plate, but then I noticed that TST recomends 3k gsk only with #4 Plate. I asked about that from TST and their answer were:
"I would expect about 250 whp (wheel horse power) and 630 torque with your truck as described. Add the 3000 governor spring kit and I’d expect about 250 whp but torque would drop to about 300. That is the reason we don’t recommend a 5, 6, or 8 plate with the governor springs. The #4 plate would give you about 300 whp and 700 torque with or without the springs."

Then I asked it from BD-power(which plate I have) also and their answer were:
"The info you received from TST is totally incorrect. The RPM Gov springs are totally separate from the Cam plate and do 2 totally different jobs. The Cam plate controls the amount of fuel and the Gov Spings control the RPM of the pump. You can put 3000 RPM gov spings in a stock pump and still see a huge improvement.
I would have no concerns in running the 3000 rpm gov springs with the cam plate you have and will will lose no hp or torq but will gain hp in the higher RPM’s."

Which one to believe? Should I get 3k gsk with #6 plate or not? Does anybody have experience how 3k gsk works with 5, 6 or 8 plate?

 

I'd do the springs, like BD said they control two different things.

Do you still have your stock plate? You could always grind it and use it if you don't like the #6 and springs.

 

Do The 3GSK!!! It only controls the rpm at which the pump starts to defuel. You will be absolutely amazed at the difference that one mod will make.

If you go higher than a #6 plate, plan on tranny upgrades in the very near future. Autos cant handle much torque without some mods and a standard will need a better clutch.

If your trans is already modded, you can grind the plate to a 0 profile slide it forward and adjust it properly, loosen the AFC starwheel and slide it forward, Then you will be.

BUT before you go all out you need to get some gagues EGT fuel pressure boost. Cause with mods mentioned above Exhaust temps and Boost pressure rise really quick.

 

do the springs it helps alot

 

ya i agree do the springs , hell i'm putting a 4k gsk in mine and a 35 tst plate and bosch 300s and my diesel guy i use said i will not loose any power and probably even gain some.

 

The springs raises the power past the stock Threshold in terms of the RPM. Not a widely commercialized product, but do a dyno before and after. Before overall power will drop off at 2400, regardless of plate. After, it'll hold up till redline, which the cummins easily handles.

 

do the 4k gsk, amazing power band. pulls like youre at 1800 rpm ALL the time. i havnt done valve springs yet so i just keep it below 3200 but man its awesome. kinda like a first time fuel plate mod all over again.