The 348, badged 348 tb for the coupé (Trasversale Berlinetta) and 348 ts (Spider) for the targa versions, features a normally aspirated 3.4-litre version of the quad-cam, four-valve-per-cylinder V8 engine which was originally found in the 288 GTO sports car. As with its predecessors, the model number was derived from this configuration, with the first two digits being the displacement and the third being the number of cylinders. The engine, which produced 300 hp (224 kW), was mounted longitudinally and coupled to a transverse manual gearbox, like the Mondial t with which the 348 shared many components. This was a significant change for Ferrari, with most previous small Ferraris using a transverse engine with longitudinal transmission. The "T" in the model name 348 tb and ts refers to the transverse position of the gearbox. Overall, 2,895 examples of the 348 tb and 4,230 of the 348 ts were produced.
The 348's styling differed from previous models with straked side air intakes and rectangular taillights resembling the Testarossa. The F355 that replaced it returned to the styling cues of the 328 with round tail lights and rounded side air scoops. Fifty-seven "Challenge" models were built for owners who wanted a more "track-ready" car.
The 348 was fitted with dual-computer engine management utilizing twin Bosch 2.5 Motronic ECUs, double-redundant anti-lock brakes, and self-diagnosing air conditioning and heating systems. Late versions (1993 and beyond) have Japanese-made starter motors and Nippondenso power generators to improve reliability, as well as the battery located within the front left fender for better weight distribution.
U.S. spec 348's have OBD-I engine management systems, though European variants do not come with the self-test push button installed, which is needed to activate this troubleshooting feature.
Similar to the Testarossa but departing from the BB 512 and 308/328, the oil and coolant radiators were relocated from the nose to the sides, widening the waist of the car substantially, but making the cabin much easier to cool since hoses routing warm water no longer ran underneath the cabin as in the older front-radiator cars. This also had the side effect of making the doors very wide.
The 348 was equipped with a dry-sump oil system to prevent oil starvation at high speeds and during hard cornering. The oil level can only be accurately checked on the dipstick when the motor is running due to this setup. The 348 was fitted with adjustable ride-height suspension and a removable rear sub-frame to speed up the removal of the engine for maintenance.
This vehicle also served as a test mule for the Ferrari Enzo. Three of these were made.
Between 1992 and 1993 Ferrari made 100 units of 348 Serie Speciale of tb and ts versions. It was a limited edition only made for US market. The revised engine produced 312 bhp (229 kW) at 7,200 rpm. Externally, the grate between the taillights was removed and a larger front spoiler was fitted. The rear track was wider by 25 mm. An additional 15 units were also made with Kevlar sport seats.