312
The 312 in³ (5.1 L) engine came out for the 1956 model year and was again used in high-end Ford and Mercury cars, including the Thunderbird.
Bore and stroke dimensions of the 312 V8 were 3.80" X 3.44".
Depending on model year and application, the 312 was available with a single 2- or 4-barrel carburetor, two 4-barrel carburetors, and with or without a McCulloch (Paxton) supercharger (1957 only).
All 1956 U.S. Mercury models were powered by the 312 in³ (5.1 L) V8 breathing through a 4-barrel carburetor. At the beginning of the model year, a 210-horsepower version with 8.0:1 compression ratio powered Mercury cars with manual transmissions (including 3-speed plus overdrive), while a 225-horsepower version powered cars with automatic transmissions. The 225-horsepower version had an 8.4:1 compression ratio. Later in the model year, a 235-horsepower version with 9.0:1 compression ratio became available. All 1956 Mercury engines had gold-painted blocks and heads. The 210-horsepower version had red valve covers and air cleaner, while the 225-horsepower version had blue valve covers and air cleaner. The 235-horsepower version had argent silver valve covers and air cleaner. A dealer-installed "M 260" engine kit was released in January 1956. The kit consisted of a hotter camshaft, revised cylinder heads, and an intake manifold mounting two 4-barrel carburetors. The kit was advertised as boosting the Mercury 312 V8 to 260 horsepower.
The last regular application of the 312 V8 in the U.S. was for certain 1960 Mercury models. Though considered to be a high performance engine in 1956 and 1957, it was downgraded to an "economy" engine with low compression and 2-barrel carburetor by 1960.
Read more about this topic: Ford Y-block Engine