https://www.hemmings.com/magazine/hmn/2010/08/1961--63-Pontiac-Trophy-4/3632031.html 1961-'63 Pontiac Trophy 4, Hemmings Motor News August, 2010] The other part of the pioneering Tempest drivetrain was a rear-mounted transaxle that was coupled to a torque shaft arcing in a 3 inches downward bow within a longitudinal tunnel.