Cylinder heads determine the personality of an engine as much as the camshaft and induction
system do. Modern Ford V-8 engines have always struggled to make power using stock
components for one basic fundamental reason—port size and bowl design. One trick has been to
open up the ports with grinding and polishing to improve air flow. Another popular performance trick
has been to fit the 221, 260, 289 and 302 engines with 351W heads to improve power.
Ford looked to its own parts shelf for power when it conceived the Boss 302 engine (basically
nothing more than an old hot rodding trick), making a cylinder head swap from the 351 Cleveland
engine family when it debuted for 1970. The 351C’s large-port cylinder heads worked wonders on
the 302 engine because they flowed huge quantities of air at high rpms. Simply put, they made
torque on the high end. They weren’t much for low rpm street use, however.
Small-block Ford cylinder head identification is straightforward and fairly easy if you know what to
look for. The most important issue to remember is casting number versus the cataloged Ford part
number. Rarely are the two ever the same. What we’re concerned with most here are casting
numbers found on the castings themselves.
221/260
The 221 cylinder head is identifiable by observing its small, kidney-shaped 45cc chambers and 1.59
/1.39-inch valves. These heads are typically numbered C2OE or C3OE and are all virtually the
same. The 260 heads have slightly larger, kidney-shaped chambers at 54.5cc chambers with the
same size valves as the 221. These heads typically have three possible casting numbers—C2OE-
F, C3OE-B, or the improved C4OE-B 260 head introduced in February of 1964, with larger 1.67/1.
45-inch valves and same 54.5cc chambers.
The 221/260 heads sport small 45cc and 54.5cc chambers respectively, which is great for
compression. Their small ports don't do much for power, however. Valve size is 1.59/1.39-inches
intake/exhaust. An improved 260 head for 1964 has larger 1.67/1.45-inch valves like the 289.
289
The 289 head was available in several configurations beginning first in 1963. Like the 260 head,
the 289 head has 54.5cc chambers with more recessed sparkplug penetration in a high-swirl
design. What’s more, valve sizes were the same as the 260’s at 1.67/1.45-inches. The 289 head
casting numbers were typically C3AE-F, C3OE-E and F and C4AE-C from 1963-64. Casting
numbers evolved to C5DE-B, C6DE-G and C6OE-M from 1965-66. C6DE-C and C6DE-E were
smog heads machined for the Thermactor air pump system on California sales district bound
vehicles beginning in the 1966 model year. Using a Thermactor head does not adversely affect
power. The Thermactor air pump manifold ports can be plugged and the head used without the
Thermactor system. If you’re building a vehicle originally equipped with Thermactor, your cylinder
heads must be a casting equipped with the Thermactor ports. Non-Thermactor heads cannot be
modified for the Thermactor manifold.
The 289 head has a slightly larger chamber than the 221/260 at 54.5cc. The 289 head is
identified by the "289" in the casting as shown. Earlier castings for the 221 and 260 don't have
this identifying mark.
Beginning May 2, 1966 in production, the 289 head was revised for rail-style rocker arms. Push rod
guide holes cast in the heads were eliminated with the rail-style rocker arms. Numbers to look for
are C7OE-A, C7OE-B, C7OE-C, C7OZ-B and C7ZE-B from mid-1966 through 1967.
From 1962 until May 2, 1966, all 221/ 260/289 engines had pushrod guides cast in the cylinder
head. Beginning May 2, 1966, Ford went to a rail-style rocker arm where the rocker is centered
at the valve. The rail-style rocker arm is on the left. The valve cover also changed with the
advent of the rail-style rocker arm. Pent-roof valve covers cleared the rail-style rockers.
For the 1968 model year, the only part numbers to look for are C8OE-D, C8OE-L and C8OE-M for
the 289, which employ lower compression 63cc chambers for use on the 289-2V engine that year.
Despite changes in part and casting numbers, all of these 289 heads are basically the same except
for machined-in provisions for Thermactor. The main thing to watch for in changes is valve and
combustion chamber sizes. Part and casting numbers are directly tied to these changes.
The 289 High Performance cylinder head is a unique casting. The Hi-Po head has cast-in valve
spring pockets that maintain spring stability at high revs. This head also has screw-in rocker arm
studs. These features make this head very desirable for racing and street performance
applications. Valve size is the same as the standard 289 head through 1967. The 1967 289 High
Performance service head has slightly larger ports while keeping the same sized valves. The Hi-Po
head number to look for is C3OE, which is the 1963 head with small 49.2cc chambers (for higher
compression). This head has the smaller valves—1.67/1.45-inch. Beginning in 1964, the 289 Hi-Po’
s intake valve size increased to 1.78-inches where it remained through 1967. Combustion chamber
size increased to 54.5cc for 1964, just like the standard 289 head. Numbers to look for here are
C4OE-B, C5OE-A and C5AE-E. These heads are obvious at a glance. Just look for the valve spring
pockets and screw-in studs.
The 1963-67 289 High
Performance head is easily
identified by the double-dot
"289", valve spring pockets and
screw-in rocker arm studs. Note
the pushrod guides cast in the
head. The 289 High
Performance engine was never
fitted with rail-style rocker arms.
Despite the 289 High Performance head’s reputation for rarity, the aftermarket cylinder head
industry has taken the spotlight off of the Hi-Po head. Cost considerations and a better design in
the aftermarket have made the 289 High Performance head less desirable when performance is the
only goal. Where originality is important, these heads are quite valuable at approximately $600 a
set bare, in good condition. Complete, they can net as high as $1200.
