Each and every Gearstar transmission built is calibrated to the customer’s truck. The process is to speak with a builder and specify how the truck will be used, including the rearend gear ratio and the height of the tires. The switch from the ’73’s TH400 to the TH350 saves 15 pounds of weight, bringing the 350/350 combo in at almost 200 pounds less than the truck’s original 454/400 powertrain. On a side note, I bought the ’73 minus its original 454/400 drivetrain. In fact, the truck was missing its original motor mounts and transmission crossmember so I had to figure out what needed to be in place before the 350/350 could be installed. All in all, my 400-plus horsepower 350/350 combo came in for well under $5,000, and that’s not a bad deal in anyone’s book. CT