The Studebaker Lark convertible X-frame was chosen for the Avanti chassis. The chassis layout, including engine position, is the same as the Lark and both wheelbase, 109 in., and tread, 57.4 in. front and 56.6 in. rear are the same. Overall length is 192 inches, that's 16 feet, a four-seater touring car size more than a sports car size. Chassis modifications include a stiffer anti-roll bar at the front end, and radius rods that supplement the rear semi-elliptic leaf springs. The suspension combines the heavy-duty coil springs of the Lark police car with the 5-leaf semi-elliptics of the station wagon. The rates at the wheels are 110 lb./in. at the front and 136 lb./in. at the rear.
The Avanti frame has tremendous structural strength and torsional rigidity. (Note the "X" member and the size of front cross-member.) An effective combination of radius rods, stabilizer bars, hydraulic shocks, coil and semi-elliptical springs provide outstanding and precise handling characteristics.