1958 Dodge

1958 was the last year for the Dodge poly and was the base V8 in Coronets (with a two barrel) and Royals (with a four barrel). The Dodge Hemi's last year was 1957, and only with the D500 or Super D500 option. In 58, all Custom Royals got the new B motor, in 350 and 361 inch versions, all of which were optional on Coronets and Royals. Top 58 Dodge motor was a Super D500 dual quad 361 with 320 hp.

In 1959 Dodge was given the 318 Plymouth poly, bored .040 over to make it a 325 or 326 (depending on source). That was a one year only motor. 318 poly became the base V8 in 1960 and remained so through the 1966 model year (in the US). (1959 also saw the introduction of the 383; and the 350 disappeared.)

Someone mentioned DeSoto above. The base DeSoto Firesweep in 57 and 58 dropped a DeSoto rear body onto a Dodge chassis with Dodge running gear and a Dodge front clip with a DeSoto front bumper. The Firesweep had the same 122 inch wheelbase of the Dodge and (I assume) the same frame. The Firedomes and Fireflites, however, used a 126 inch wheelbase frame, which would not be interchangeable with Dodge.

As an aside, not really important here, the 57 Firesweep used the Dodge 325 poly, but the 58 Firesweep got the new B engine, with 350 cubes. Looks just like a 383, but it's a 350. Higher line 58 DeSotos got 361s. 1957 was the last year for the DeSoto Hemi.

The Chrysler poly, Dodge poly and Plymouth poly were three completely different motors, with virtually nothing interchangeable between them. Chrysler and Dodge poly motors were essentially each brand's hemi motors with poly heads. The 318 poly designed originally for Plymouth became the corporate small block, and later was given wedge heads in 273, 318, 340 and 360 versions, all of which shared the Plymouth poly's basic architecture designed for the 56 Plymouth models.

One final note: someone mentioned the lack of a Park position for the trans. Until 62 Chrysler Corporation's automatic transmissions - Powerflite or Torqueflite - had no parking pawl on the trans. Instead, they put a miniature brake drum on the rear of the trans to use as a parking brake (without any parking brake mechanism in the rear brakes). And even when aluminum Torqueflites were introduced for the 62 model year, Chrysler kept the brake drum on the tail of its aluminum Torqueflite to be used as a parking brake, with no parking pawl like Dodges and Plymouths got (along with what we called emergency brakes, but were really parking brakes, at the rear axle).