I have a 97, which has the same injection pump as the 98 12valvers do, and the bigger delivery valves made a big difference in my pump. The governor spring kit also made a huge difference in the engine's power band.
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520 Rear Wheel H. P. and locomotive level torque = 15. 5 sec @ 97 mph with the rear wheels spinning in 5th gear going through the traps in the quarter mile. No slicks here, pal, no fancy auto transmission, just the truck in full street trim, 7400 lbs. of Auto Wurks Diesel/BD Performance raging, fire-breathing DIESEL POWER
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520 Rear Wheel H. P. and locomotive level torque = 15. 5 sec @ 97 mph with the rear wheels spinning in 5th gear going through the traps in the quarter mile. No slicks here, pal, no fancy auto transmission, just the truck in full street trim, 7400 lbs. of Auto Wurks Diesel/BD Performance raging, fire-breathing DIESEL POWER