GM HP & Torque


If you study the performance curves below you will see two major benefits of GearSplitting. As an example we’ll use the TH400 or 4L80E trans chart with a Vortec 7.4 (454). Gears are multipliers of torque so at 3,000 rpm in 2nd-over the torque multiplier is 4.73 where without the GEAR VENDORS you would get into 2500rpm in 3rd-direct at 4.10. The difference in engine torque is only 10lbs ft. but the difference in the multiplier 4.73 vs 4.10. That’s over 18% more working torque.

At this same moment horsepower at 3,000rpm is 260 instead of 210 @ 2500 which is over 23% more horsepower with all the reliability of your stock powerplant. To figure the drop in rpm or torque multiplier from on gear to the next calculate as follows: Final Drive Ratio of the gear you are shifting to, divided by the gear you are shifting from, minus 1, times 100. The difference from 1st-over to 2nd is even more dramatic. This is why if you are towing or loaded heavily, the best way to reliably improve performance is with the GEAR VENDORS UNDER/OVERDRIVEâ„¢. It’s the same reason the big 18 wheelers have 2 and 3 speed auxiliaries for 10 to 15 or more gears.

Click on graphs to enlarge.


GM 5.7L (LOS)


GM 7.4L (L19)


GM 6.2 V-8 (Diesel (LH6)


GM 5.7L Vortec (L31)


GM 6.5 V-8 Diesel (L65)


GM 7.4L Vortec (L29)