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Not all 289 and 302 blocks were cast at Cleveland. Here’s a 289 block that was cast at Windsor with the “WF” Windsor foundry marking.
One example might be “5A26” (January 26, 1965), which means year, month, and day of casting or manufacture. If the date code is cast into the block, it indicates the exact date the block was cast. If it is stamped into the block, it indicates the engine’s exact date of engine assembly.
All 289 High Performance V-8s were stamped with the vehicle identification number here along the passenger-side pan rail. This engine is from an early 1966 Shelby GT350, which is actually a holdover ’65 with a Ford 1965 VIN. It is Ford Blue, but should have been painted black, which is the correct color for 1965.
Mexican blocks (289 and 302) are easily identified by the round and “D” bosses at the front of the block. Although it has long been believed Mexican blocks have a higher nickel content, this isn’t true. These blocks weigh exactly the same as their U.S. counterparts. Their difference is their 15/16-inch-wide main caps.
This is the Mexican block’s wider 15/16-inch main cap, which closely resembles the 289 High Performance main cap. The wider main caps were for durability in unimproved road conditions.
If you find a matching-number block with cylinder bores that have been bored to 4.030 inches or larger, the block can be sleeved by a qualified machine shop and returned to service. The cost to sleeve a block is approximately $100 per cylinder depending upon the shop and area. The good part about sleeving a used block is the seasoned iron from steady cycling of heating and cooling over time. Sleeving is discouraged if you’re going racing because, no matter what anyone tells you, there isn’t enough stability with iron bores. New-old-stock Ford service blocks from the 1960s are expensive and hard to come by but can still be found.
Check any block you’re considering for cracks and severe deck warping before machine work is performed. This process can be accomplished by any qualified machine shop before expensive machine work begins. As a rule, small-block Fords rarely suffer from cracking unless there has been a severe overheat or extraordinary circumstances such as an accident or the block having been dropped. Weak spots are generally around the decks near cylinder head bolt holes, cylinder bores, and main saddles.
Mexican 289/302 blocks are believed to have a higher nickel content, but this is not true. Mexican blocks and their north-of-the-border counterparts weigh virtually the same, which debunks the high nickel content theory because nickel adds weight to an iron casting. A Mexican 289/302 block is better because of its wider 15/16-inch non-tapered main bearing caps (as you see on 289 High Performance blocks). Mexican blocks are a good source for wider main caps. If you use them on another block, have a machine shop measure and line bore/hone them to the proper size.
Ford’s limited-production 1969–1970 Boss 302 engine block is highly sought after for its four-bolt main caps, heavier main webs, thicker decks, and screw-in block plugs. Because fewer cores are available today, it isn’t racers going after these blocks but restorers looking for authentic date-coded Boss blocks.
Ford Mexican blocks have “M” casting numbers such as “C8AM-6015-B” and the casting date code. If you find a Mexican block that is beyond salvaging, you can use the wider main caps on another block. The block and caps have to be line-bored/honed to achieve proper fit.
Five basic Boss 302 block castings were produced: C8FE, D0ZE-A, D0ZE-B, D0ZE-C, and D1ZE-B. C8FE is the 1968 302 Tunnel Port block, which was also used in production 1969 Boss 302 Mustangs and Cougars. Most common are the D0ZE and D1AE Boss 302 block castings. D1ZE-B is a Ford replacement service block. Because Boss 302 engines failed mostly due to piston failure, there are plenty of service blocks available.
As with the earlier 221, 260, 289, and 302 blocks, overbore for the Boss 302 block is limited to 4.040 inches, and it is suggested no greater than 4.030 inches, especially if you intend to take it to 7,000 to 8,000 rpm. You can sleeve a Boss 302 block for about $100 per cylinder and go back to a standard bore.
This is the Boss 302/302 Tunnel Port block, which is the only small-block Ford (Fairlane V-8) produced with four-bolt mains. The Boss 302/302 Tunnel Port block sports screw-in freeze plugs and 4.000-inch bores.
Boss 302/302 Tunnel Port blocks have screw-in freeze plugs due to the high cooling system pressures that they run at high RPM.
Compared to the 221/260/289/302, the 351-ci Windsor block is a taller deck with additional webbing in front on top, which makes identification easy because it has a wider block. The 351W has a 1-inch-taller deck to accommodate the increased 3.500-inch stroke. The 1969–1971 351W blocks appear to be stronger than those after it based on having a higher nickel content.
Early 351W blocks are numbered C9OE and D1AE. One other option is 351W blocks cast in Mexico for high-performance applications. They are difficult to come by. They pop up from time to time in U.S.-built Fords and Mercurys. Like the 302 blocks mentioned earlier, these blocks weren’t limited to Mexican-built vehicles.
A Boss 302 block with a “C8FE-B” casting number is a 1968 302 Tunnel Port block. Aside from the casting number, they’re virtually identical to the production Boss 302 blocks of 1969–1971. This particular block was cast December 5, 1968. According to Randy Ream of the Boss 302 Registry, C8FE-B blocks wound up in production 1969 Boss 302 Mustangs and even some early 1970 units.
The Boss 302/302 Tunnel Port block has this AE 302 marking in the lifter valley. Not all Boss 302 blocks were marked this way. This is an early 302 Tunnel Port block, which ultimately became the Boss 302 block.
This is a Boss 302/302 Tunnel Port block with the vehicle’s consecutive unit number stamped in the valley end rail. Because this is a C8FE-B block, it probably came from a production 1969 Boss 302 Mustang.
