The 1958 Pontiac Bonneville features a bold change in design from previous models, including a shrouded four-headlamp front end, lower stance and concave-shaped rear quarter panels. It is powered by a 370-cubic-inch V-8 engine with an overhead valve and a bore and stroke of 4.06 x 3.56 inches.
The super-strong forged steel crankshafts feature 2.625-inch diameter main journals, and the super-strong forged steel connecting rods have 2.25-inch diameter big-end journals. A windage tray attached to the top of the crankshaft's main caps is standard and reduces the oil's parasitic drag, increasing the effective horsepower. The differential features a typical hypoid unit with full-floating axles and a 3.23:1 gear ratio and introduced the Safe-T-Track limited-slip differential.
The Rochester mechanical fuel injection is available on some Bonnevilles as a high-end performance option. Other options that are present on some Bonnevilles include a speed alert buzzer, removable transistor radio, rear seat speakers, bucket seats and a power driver's seat.
The transmission is a Strato-Flight Hydra-Matic four-speed automatic transmission. The frame is an X-type design that Pontiac called the Aero Frame. The steering features a durable Saginaw recirculating-ball steering gearbox with power assist. The suspension consists of unequal length A-arms with tube shocks and coil springs.