When it comes to rowing your own gears in 1973-87 Chevy pickup trucks, it used to be you had to settle for the old truck-manual transmission or cobble something together. Thanks to American Powertrain, that is no longer an issue. The Squarebody Chevy trucks are rapidly growing in popularity, so American Powertrain introduced its new Pro-Fit five- and six-speed systems.

This new system features the rock solid TREMEC TKO five-speed or the MAGNUM six-speed transmission with all the installation parts you need to upgrade our classic hauler. The Pro-Fit system includes American Powertrain’s Revolutionary shifter mechanism with an OE four-speed shift position, the company’s adjustable X-Factor crossmember and 3 1/2-inch DOM driveshaft, speedometer hookup, reverse-light wiring, and your choice of shifter knobs. Several different shifter handles are available for bucket and bench seat applications.

The transmissions are compatible with the original flywheel, clutch linkage, and most OE spec clutches. If you’re looking for clutch actuation of the hydraulic variety, a hydraulic-clutch upgrade is also available.

We’re told the five-speed Pro-Fit Kit prices start at $3,995 including the transmission and are ready to ship now. All Pro-Fit kits are covered by American Powertrain’s two-year warranty and come with free comprehensive tech support.

Hydraulic-clutch kits are also available.

30- to 50-percent increase in fuel economy
Low-RPM cruising for greatly reduced driver fatigue and an improved highway driving experience.
Reduced engine wear leading to longer engine life
Cooler engine operating temperatures

TKO Gear Ratios
TKO 500 – 3.27, 1.98, 1.34, 1.00, 0.68
TKO 600 – 2.87, 1.89, 1.28, 1.00, 0.64 OR 0.82

T56 Magnum Gear Ratios
Close Ratio 2.66, 1.78, 1.30, 1.00, 0.80, 0.63
Wide Ratio 2.97, 2.10, 1.46, 1.00, 0.74, 0.50

Kit includes:

AP Revolution shifter mechanism locates shifter – will fit bench or bucket seats
Seamless DOM driveshaft assembly – race-balanced, solid U-joints
Driveshaft slip yoke – cryogenically hardened steel
X-Factor aluminum adjustable Squarebody crossmember

Pilot bearing – stainless rollers, grease pre-pak
Weather sealed reverse-light harness
Electronic speedometer conversion
Shifter knob
Hardware, instructions, warranty

Bell housings, clutches and shifter available as well. Got an LS swap? We can make it easy.

American Powertrain recommends using its hydraulic clutch, but you can use a stock pedal and factory hydraulic master cylinder with some model years (Hydramax bearing adapter line required). Complete Hydramax System available for Squarebody.