Making power and getting it to the ground are two different things. Once you’re making the power, you quickly discover the weak links in the drivetrain. One area that seldom gets attention is the driveshaft. Trick torque converters, clutches, transmission ratios and bitchin’ rearend parts tend to overshadow the lowly driveshaft. Most hot dogs just use the stock piece until it breaks, scattering parts all over the dragstrip, or worse, punching a hole through the floor of the car.

Torque, weight and good traction all combine to make things tough on a driveshaft. For example, 400 lbs-ft of torque through a Turbo 400 with a 2.48:1 first gear ratio and a converter torque multiplication ratio of 2:1 will crank almost 2000 lbs-ft of torque through the driveshaft on the launch. Mark Williams Enterprises (M-W) has been building stout driveline components for drag race cars for years and applies this experience to build killer driveline components for all kinds of drag race applications.

Stock driveshafts are usually constructed out of .065-inch-wall-thickness 1010 mild-steel tubing, which is fine for production cars but not for the abuse handed out by these quick Super Street cars. Williams offers two different shaft materials. The street application is a drawn-over-mandrel (DOM) 1020 shaft using Spicer cast, welded-on yokes. But for fast, primarily drag race applications, M-W usually recommends a 3-inch-diameter, 4130 chrome-moly steel, .083-inch-wall-thickness tube that uses forged Spicer shaft yokes that are much stronger. A special fixture properly aligns the yokes and limits total shaft runout to less than .010 inch before the yokes are Tig-welded in place. Balancing also keeps the shaft within 2 inch-grams to prevent vibration.

Stronger transmission and rearend yokes are also necessary. M-W makes custom 4140 steel replacement yokes that are direct replacements for all the popular GM, Ford and Chrysler applications. These yokes are far stronger than stock pieces, and are offered for both the transmission and the rearend. U-joints are another important link in the chain. M-W specifies the 1350 series Spicer U-joints originally used in 1-ton truck applications for their durability.

Any fast drag race car needs some type of performance driveshaft, U-joints and yokes to ensure the safe application of power to the rear tires. The last thing anyone wants is to experience the terror of a flailing driveshaft that’s decided to come right up through the floor of the car.