The 1961-63 Pontiac Tempest was based on Chevrolet’s Corvair platform, but featured the engine up front.

Because the Corvair platform did not allow for a typical rear-drive driveshaft tunnel, a rear-mounted transaxle was coupled to a torque shaft arcing in a 3 in (76 mm) downward bow within a longitudinal tunnel. To combine flexibility with strength in the proper proportion, the shaft was forged of SAE 8660 steel (high nickel, chrome and molybdenum alloying percentages) for torsion bar specifications. This joined the forward engine and the rear transaxle (therefore no transmission hump) into a single unit, helping to reduce vibration. The design, known as “rope drive,” had only been seen previously on General Motors’ 1951 Le Sabre concept car.

The combination of a rear-mounted transaxle and front-mounted engine very nearly gave the car an ideal 50/50 front/rear weight distribution. This, along with a four-wheel independent suspension, helped make the Tempest a nimble-handling car for the era. The front engine/rear transaxle design also eliminated the driveshaft/transmission tunnel in the front of the passenger compartment, while lowering the driveshaft tunnel in the rear compared with a conventional front engine/front transmission layout.