Ford Small-Block Engine Parts Interchange. George Reid
1 through 9 = 2001–2009
A = 2010
B = 2011
C = 2012
D = 2013
E = 2014
F = 2015
The alphabet continues accordingly after 2015 with “G” for 2016 and so on. Again, Ford does not use the letter “I” or “L” because it’s too easily confused with the number “1.”
Second and Third Positions
For example, “R3” indicates Mustang. “L4” is for Maverick. “R2” is for Falcon, and so on.
Fourth Position
Engineering Department responsible for the part.
Basic Part Number
Same as prior to 1999. A cleaner numbering system, however, with left and right specifics. Easier to follow and understand.
Suffix
Same as prior to 1999. Again, easier to follow and understand.
The 1962–1963 221-ci and 1962–1964 260-ci engines employ five-bolt bellhousing blocks with a bore of either 3.500 (221) or 3.800 (260) inches. Casting numbers are C2OE, C3OE, or C4OE. The location of these casting numbers depends on the block. In 1962, block casting numbers were cast into the rear lifter valley rail on top. In 1963–1964, they can be found just above the starter. Casting date codes in 1962–1964 are in the block above the starter. These blocks are easy to spot because their 3.500- and 3.800-inch bores are smaller than the standard 4.000-inch found on the 289 and 302.
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