the truck with stock springs will actually start to defuel at around 2100 rpm, but it will fuel to around 2700 going down the road wide open in 4th gear (or 5th or 6th if you have a manual). Change the govenor springs and engine will start to defuel around 2700 rpm but you wont really feel it too much till your around 3200rpm, or for some reason mine are that way w/o even puting any shims or tighting the springs any more then the stock protrusion.

 

on my dyno sheet it made peak horsepower at 2400.

 

ill have to check my dyno sheet and see what it said peak power was at.

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just found my dyno sheet. max power about 2400rpm probably gonna order a GSK soon as i get my clutch taken care of.

 

just found my dyno sheet. max power about 2400rpm probably gonna order a GSK soon as i get my clutch taken care of.[/QUOTE]

maybe its a 97 thing

 

My truck was defueling around 22 to 2300 rpm's. With the 3k GSK I defueling around 26 to 2700 rpm's. It was not that noticable until I installed the new turbo now I defueling real quick. I ordered the 4k GSK for it. I can not get the max boost out of the turbo because of the defueling.
If anyone is going to a 4K make sure get 60# springs. You float the valves with the higher rpm's!

 

you need the springs only if exceding 3200rpm

 

ill probably get a 4k gsk with valve springs but maybe away before i would get it all installed

 

My truck also Starts to defuel at about 2300 but a i can stay in it till 3300 but it doesnt pull like it does early in the rpm range