delayed high rpm shift at street operation. although you can crank the shift points down a tad and maintain streetability.this is done by the modulator. note torque converter stall speed and camshaft efect the shift pionts. as the lower idel vacuum raise the shift point also the converter stall efect the shift feel (fimness) although it shifts hard it will not chip the tires on gear change. converters and shift kit parts are getting rare for this model. the C4 or c6 has more performance parts availble. now the aod and the aode are pecoming more popular.