277 CID

The 277 "Hy-Fire" was the first A-block engine, produced for 1955 in the fall of 1954 and sharing almost nothing but the basic concepts with other engines built by Chrysler. Bore is 3+3?4 in (95.3 mm) and stroke is 3+1?8 in (79.4 mm; 3.13 in) for a piston displacement of 276.1 cu in (4,525 cc). It was replaced by the 301 in 1957, except for in low-priced Plaza models where it continued to be used during the 1957 model year.

301 CID

The Plymouth 301 replaced the 277 in 1957. Its piston displacement is 300 CID, using a 3.91 in bore. These dimensions have no relation to the 1955 Chrysler 301 that was a de-bored 331 block.

303 CID

The 1956 Plymouth 303 displaces 302.5 CID and uses the same connecting rods as the 277; the bore is 3.81 in and the stroke is 3.31 in.

This engine was used in the following vehicles:

• 1956 Dodge Custom Royal (Canadian)
• 1956 Chrysler Windsor (Canadian)
• 1956 Plymouth Fury, 240 bhp with 4-barrel carburetor
• 1957 standard on all 118 in wheelbase Dodges and Plymouths

313 CID

A 313 CID version of the A engine was produced from 1957 to 1967 primarily for Canadian and export markets. This engine has a bore of 3.875 in and the common 3.3125 in  stroke, and was used in the following vehicles, amongst others:

• 1957 Canadian Dodge Custom Royal
• 1957–1964 Australian Chrysler Royal
• 1958–1967 standard or available in all Canadian-market Dodges and Plymouths except Valiants, Barracudas, and Darts
• 1961–1963 British Bristol 407
• 1963–1965 British Bristol 408 Mark I

318 CID"

The 318 is the most common version of the "A" engine, produced from 1957 through 1967 when it was replaced in all markets by the LA 318. Only Plymouth used this 318 in 1957 and 1958, but it was shared with the other Chrysler divisions from 1959 on. It displaces 318.2 CID and has a 3.91 in bore and the 3.3125 in stroke.

A special version of the A block, called "V-800", was offered in 1957 and 1958. It used two four-barrel carburetors to produce 290 HP, making it the highest-output A block. It was available in the 1957 and 1958 Plymouth Fury, but was also an option on all Plymouth models. It was used on a wide variety of Chrysler products in Canada, right up to the end of production in 1967.

Bristol Cars introduced the 318 in the Mark II model of their 408 in 1965, and continued to use it in the succeeding 409 and 410 until 1969. From 1962 until early 1965, Checker Motors used this engine for their Aerobus limousines.

326 CID

The 326 was launched in 1959. Its actual piston displacement is 325.25 CID but it was marketed as a 326 to avoid confusion with the Dodge Red Ram 325 block. The 326 uses the same 3.3125 in stroke as the 318, but with the largest bore of any A engine at 3.953 in. It used hydraulic tappets, unlike the earlier A engines, and was available in the 1959 Dodge Coronet.