My brother-in-law owns a 1994 Dodge 3500 diesel with a 5-speed. It has slight modifications including a k&n air filter, aftermarket exhaust, and a tst products torque plate that is supposed to give it 270 hp and 475 ft lbs. This truck has a tremendous amount of low end torque. It seems like the peak power is from about 1200 rpm to 2500 rpm. After about 2500 rpm the power falls off. This seems to a characteristic of the older trucks. What can be done to make it pull as hard up to 3000 rpm like the newer ones? Thanks