The small-block Ford’s basic block architecture didn’t change much over its long production life. This is a 289 block cast at Windsor with a “WF” casting code. Not all 289/302 blocks were cast at the Cleveland foundry.
Block-deck cooling passages on the 221 and 260 are triangular shaped as well, which makes them different from the 4.000-inch-bore 289 and 302. Early 1962 221 and 260 blocks had two 1½-inch freeze plugs on each side, which became three freeze plugs in 1963 with the arrival of the 289. These early blocks are also identified via engine-mount bolt-hole spacing; the earliest 221/260 blocks are 5.940 inches apart along with two freeze plugs instead of the traditional three you see most often. Revised engine-mount bolt-hole spacing to 7.000 inches changed in the 1963 model year to reduce noise, vibration, and harshness.
The 289-ci engine entered production in the 1963 model year with a five-bolt bellhousing bolt pattern just like the 221 and 260, along with the 7.000-inch mounting bolt holes and three freeze plugs on each side of the block. Five-bolt-bellhousing 289 blocks have casting numbers of C3OE, C3AE, C4OE, C4AE, and C4DE.
Beginning with the 1965 model year, Ford revised the 289 block to a six-bolt bellhousing bolt pattern to improve noise, vibration, and harshness. Block casting numbers are C5AE and C6AE. The 289 High Performance V-8 had the same block as the 289-2V and 289-4V with the exception of wider main bearing caps. Standard 289-2V and 289-4V main bearing caps are 15/16-inch wide at the block main saddle; they taper as they rise to the top at the casting and cap numbers. The wider 289 High Performance main bearing cap is 15/16-inch wide at the block and does not taper. This difference applies to both five- and six-bolt-bellhousing 289 High Performance blocks.
The 302 block appeared for the first time in the middle of the 1967 model year in 289 applications with a C8AE or C8OE casting number with a “302” in the valley area. What made the 302 block different than the 289 was .015-inch-longer cylinder skirts to accommodate the 302’s longer 3.000-inch stroke. It is not uncommon to find a 1967–1968 289 engine with a 302 block.
This is a side-by-side comparison of the two small-block Ford V-8 bellhousing bolt patterns. On the left is the smaller five-bolt pattern used from 1962 to 1964. On the right is the larger six-bolt pattern employed to reduce noise, vibration, and harshness by spreading harmonics across a broader contact area to dampen sound and vibration.
The casting number was located at the rear of the block at the valley-to-manifold rail in 1962 only. From 1963 on, the casting number was located just above the starter (shown) along with the actual casting date code. This is a 260 block with a casting number of C4OE-6015-E cast on “5G26” or July 26, 1965, making it a service replacement.
The date code stamped into a block (shown) indicates the date of engine assembly. This code, “5C4R,” means March 4, 1965. It is unknown what the “R” means.
Most 221, 260, 289, and 302 blocks have these 15/16-inch-wide main caps that taper toward the casting and main cap numbers. These caps are 15/16 inch at the block mating surface and roughly 1/2 inch at the top.
The five-bolt bellhousing bolt pattern was used from 1962 to 1964 on all small-block Fords including 221, 260, and 289. This is a new-old-stock C4OE-E 260 block unearthed by a restorer in Florida.
The engine assembly date code was also stamped in the block pan rail near the casting number and date code. If you find a block that has been decked and the engine assembly date is gone, look for the stamped date code here.
The 289 High Performance block is marked “HP” with a grease pencil along with an orange paint dab. The block isn’t any different than a standard 289-2V/4V block, but it has wider main caps, also marked with orange paint.
This is the 289 High Performance engine’s wider main cap, which is 15/16-inch wide for its entire width and height. Note the orange paint marking, which made it quickly identifiable in the frantic pace of production.
The 302 block evolved after 1968 with casting revisions. Although most of these blocks are interchangeable with 289 types dating back to 1965, it is important to note that the clutch equalizer shaft pivot boss on the driver’s side was eliminated from the 302 block beginning in 1975. This means that you need a bolt-on clutch equalizer shaft pivot bracket for a 1975–up 302 block if you run a manual transmission and the classic Z-bar clutch linkage.
If you’ve found an original engine that’s never been apart, it likely has its original rear main rope seal and pin. Remove and dispose of the pin. If you forget to remove the pin, it distorts the new rear main seal, causing leakage.
Nearly all blocks have this boss. However, it was rarely used for anything. It is believed this boss was originally conceived for the vehicle identification number. However, 289 High Performance V-8s got the VIN stamp not here, but on the passenger-side pan rail in the rough-cast surface. It is unknown what “PP” means.
This is a June 1967 “302” block that was factory assembled as a 289. “C8OE” 302 blocks were cast as early as February 1967. Based on several examples seen in a variety of machine shops through the years, Ford produced a lot of 1967 289 engines using C8OE 302 blocks.
If you restore a classic Mustang or other type of vintage Ford, your search for a corresponding numbers-matching block is challenging because there aren’t as many salvageable cores as there used to be. For the purist, remember this: The block should have a correct casting number. A 1965 Mustang, as one example, should have a C4 or C5 casting number depending upon vehicle build date. Casting and engine build date codes should fall within 30 to 60 days of the vehicle build date.
