Though a lot of people mistakenly call the Ford small-block the “Windsor” V-8, the 221, 260,
289 and 302 engines were never identified as “Windsor” small-blocks by Ford Motor Company.
These engines were all produced in the Cleveland engine plant from the beginning. Ford
called this family of engines the 90-degree “V” family of small-blocks or the “Fairlane” V-8. The
351 “Windsor” small-block V-8 which was introduced in 1969 was the only V-8 engine ever
named the “Windsor” by Ford, to distinguish it from the all-new 351 “Cleveland” small-block V-
8 introduced for 1970.
Block identification is straightforward. The 221 and 260ci V-8s use a five-bolt bellhousing block
with 3.50-inch and 3.80-inch bores respectively with a C2OE or C3OE casting number. Aside
from cylinder bore size, these two blocks are virtually the same. The only significant change in
the 221/260 block is engine mount bolt hole spacing at the block. The earliest 221/260 blocks
employ engine mount bolt holes that are six inches apart, identifiable at a glance by the use of
two freeze plugs. When the bolt holes were widened to seven inches as a means to improving
noise, vibration, harshness and structural integrity, three freeze plugs were used. This change
was adopted early in production in the 1963 model year. The 221/260 blocks should not be
bored to 4.00-inches (289ci) because the risk of water jacket violation is very high. It is
recommended that you begin your small-block high-performance Ford engine project with a
289 or 302 block, which has a 4.00-inch bore from the start.
identification is the casting
number and date code found
above the starter on the
right-hand side of the block
on 221/260/ 289/302, Boss
302 and 351W/351C engines.
numbered C3OE, C3AE, C4OE, C4AE and C4DE. Beginning in the 1965 model year, the 289
had a six-bolt bellhousing bolt pattern. Six-bolt blocks were numbered beginning C5AE and
C6AE. The 289 High Performance block (1963-67) was the same as the 289-2V and 289-4V
block with the exception being wider, heavier main bearing caps. There was no difference in
the block whatsoever.
The 302 blocks appeared for the first time late in the 1967 model year as 289 engines with
casting numbers beginning C8AE and C8OE, sporting a “302” in the valley area. It is not
uncommon to find a 302 block that was cast and assembled during the summer of 1967 as a
289ci engine. Though 302 blocks looked virtually identical to the 289 block, the cylinder bores
had extended skirts to handle the 302’s .019-inch longer stroke. This extended cylinder skirt
reduced piston slap and improved stability for quieter operation. The 302 block evolved to a
certain degree in the years following 1968. While most of these blocks are interchangeable
with 289 derivatives dating back to the 1965 model year, it is important to note that the clutch
equalizer pivot boss was deleted from the left-hand side of the block beginning with the 1975
model year.
If you are restoring an old Ford or Mercury to stock condition and are looking for a matching
number block, your challenge will be greater, but not impossible. There are two considerations
for the purist. First, the block must have a Ford part number that falls in line with the model
year of the vehicle. Secondly, the date codes (casting and manufacture date codes) should fall
30-60 days prior to the scheduled assembly date code of the vehicle. An example of a date
code might be “5A26” (January 26, 1965) or “4F17” (June 17, 1964) which means the year,
month and day of casting or manufacture. One example of a Ford part number might be C5AE-
6015-E for a 289 block. Look for these numbers because they show you the way to
correctness.
deck just below the
distributor is the engine
assembly date code. This
tells when the engine was
actually assembled.
060-inch, the block can be sleeved with standard size cylinder bores for $800 to $1,000 at
nearly any machine shop. Then you will have a fresh block ready for a renewed return to
service. Finding a correct period block that hasn’t been overbored is a great challenge. New-
old-stock (NOS) service blocks that have never been assembled are out there, but they are
expensive and rarely for sale at a swap meet. Sleeving a worn out block may prove more cost
effective than buying an NOS block. The beauty of sleeving a worn-out block is its seasoned
iron which is completely settled.
blocks and bellhousings is a
very important consideration.
The five-bolt small-block
bellhousing pattern was used
through August 1, 1964 in
mass production (see table).
Six-bolt blocks and
bellhousings (shown) were
conceived to reduce noise,
vibration and harshness,
beginning August 1, 1964. All
221 and 260ci engines were
of the five-bolt design.
performed. This process can be accomplished by any reputable machine shop before the work
begins. Small-block Fords rarely suffer from cracking unless there has been a history of
overheat. Weak spots are generally found at the deck around the cylinder head bolt holes and
water passages.
The 302 block was virtually unchanged through 1975. In your search for a 302 block, we
suggest the use of the high nickel content blocks produced from mid-1967 through the early
1970s. One alternative, though not always easy to find, are the 302 blocks cast in Mexico. A
number of these blocks found their way into U.S.-built Fords and Mercurys. These Mexican
blocks weigh more, but they offer strength in a heavier casting, thus being more suitable for
high-performance use.
from the 289, yet both are
interchangeable. We suggest
the use of a 302 block with 289
internals, but not the 289 block
with 302 internals, due to the
increased stroke. The 302
block has slightly longer
cylinder wall skirts to
accommodate the small
increase in stroke length. This
reduces piston skirt noise and
play at the bottom of the bore.