Ford’s Y-Block

Closely based on the 317 cubic inch OHV engine introduced in the 1952 Lincoln, Ford’s Y-block was introduced in 1954. in the US and 55 in Australia, Overall engine design goals included room for increased displacements and compression ratios. In addition, it was a modern short stroke design that reduced internal friction and piston speed to enhance durability. Low construction costs were a factor too. One example is that the Y-block required fewer casting cores than the flathead.

Ford’s new engine family began with 239 and 256 cubic inch displacements. From the 239, a bore increase produced the 272 and 292 engines. This was followed by another increased bore and stroke to produce the 312. The Y-block was installed in Ford cars from 1954 to 1962 and Mercurys from 1954 to 1960. Starting in 1955, the Ford car base V8 was the 272 with the 292 optional in 1956 and 312 in 1957. Thunderbirds had the 292 in 1955, the optional 312 in 1956 and the 312 standard in 1957. Mercury moved from the 256 to the 292 in 1955 and the 312 became standard in 1956. Ford pickups used the 272, then the 292 until 1964. Ultimately, Y-blocks were phased out by FE engines starting in 1958. All Australian cars and utes were 272 and  the 292 started with the 59 F600 truck.

Performance development of the 312 peaked in 1957 with a centrifugal advance distributor, larger exhaust manifolds, improved intake manifold configuration and use of Holley’s new 4150 series carburetor. Heads got larger intake valves and higher compression. Ford produced single four-barrel and dual four-barrel performance options along with the famous Thunderbirds. Race prepared Y-blocks powered Ford and Mercury NASCAR stock cars. After 1957, they were de-tuned for economy, although the big valve heads were retained through 1959.

Block, Crank, Rods and Pistons

The block was designed with an extended skirt design, which means it extended past the crank centerline. Viewed from the front, the block shape resembled a Y - hence the name. The extended skirt increased block rigidity and main web support. Additional defining Y-block features were the rear mounted distributor and external oil pump.

Connecting rods were forged, and there were two different lengths. The 272/292 rods were 0.072-inch longer than the 312 rods. Rods were bushed for full floating piston pins that were retained by circlips.

Passenger car cranks were cast, while pickup cranks were forged. The major differences between the 272/292 and 312 cranks is the increased main journal diameter that was used on the 312. Rod journal diameters remained the same. On 312 blocks, the larger diameter main journal bore came awfully close to the main cap bolt holes. As a result, potential cracks could occur around the bolt holes when the main caps were torqued in place. Many builders used a 292 block (which could be opened up to a 312 bore) with a 312 crank with turned down mains for ultimate durability.

Intake, Heads and Valvetrain

Y-block heads had several unusual features. A major one was the stacked intake ports (unlike the conventional side-by-side 317 Lincoln port layout). This allowed the H-shaped intake to be less bulky. Also, the head port configuration supposedly introduced turbulence to the air/fuel mixture as it flowed through the port and entered the combustion chamber to burn at maximum efficiency.  The revised ECZ-G heads were the best OE castings, thanks to even flow between intake ports.

Another unusual feature was that all Y-blocks had a solid lifter cam using mushroom shaped lifters. Because oil galleries for hydraulic lifters were never cast in, it appears Ford never intended to install them.

Valves were operated by shaft-mounted rocker arms. rocker arm oiling occurred via a hole (later a groove in the cam journal), that directed oil through a passage in the block, head and rocker shaft stand. Due to lower quality oils, and overdue oil changes by owners, this passage could become blocked by sludge, starving the rockers. When rebuilding a Y-block, it’s important that these passages are clean.

Choosing the right block for performance and strength. When Ted Eaton and Randy Gummelt  set out to build a Y block engine for his rear engine dragster, the plan was to have an engine combination that would run an eight second quarter mile. And Randy also had his sights on the Australian Y record and with a target of an 8.99 or better et, that plan would achieve both goals. By now, it’s pretty well known that Randy ran a best of 8.15 @ 162mph at the Y Shootout during this past Labor Day weekend at Columbus Ohio so the plan was definitely a good one. In order to accomplish this it was necessary to figure out a workable combination and then to start gathering up the necessary parts that would make this combination work. Thus the plan starts to take shape as follows.

For the basic foundation, it was decided to use a C2AE-C block due to these particular castings being known for their consistent thicker cylinder walls as well as the additional main support webbing that is already present in these blocks. For an aspirated version,  normally there is  no issue in boring these particular blocks out to 3.860” (+0.110” over) but because this was to be a serious blown effort, the finished bore was targeted at a smaller 3.800” bore to maximize cylinder wall integrity and in turn reduce any chance that cylinder wall flex would potentially kill or hurt some of the power. Part of the reason for going with a 3.800” bore versus a 3.810” bore was being able to get in on a special run of Total Seal brand 1/16” wide gapless rings for a 3.800” bore that were being made for one of the Nascar teams. The 3.810” bore 1/16” wide rings were already available as an off the shelf item but being in a position to make the bore and stroke ‘square’ was more conducive to the overall plan. Because of the supercharged nature of this engine, the top ring would be gapless by design as opposed to normal practice of using a gapless style ring in the 2nd groove in a normally aspirated application.