The 1958 model year was to be the last use of the Firepower Hemi in the 300. The engine was still 392 cu in (6.4 L), but tuned to 380 hp (280 kW) as standard. Thirty-five cars were built with fuel injection and delivered 390 hp (290 kW), but the system was troublesome and most cars soon had it replaced with the standard twin-quad carburetor setup. A 300D was driven to 156.387 mph (251.680 km/h) at the Bonneville Salt Flats that year. A total of 618 hardtops and 191 convertibles were produced, in part due to a recession in the economy.