The Ford small-block (aka Windsor V8) is a series of 90° overhead valve small-block V8 automobile engines manufactured by the Ford Motor Company from July 1961 to December 2000.

This article needs additional citations for verification. (May 2010)

Quick Facts Overview, Manufacturer ...

Ford small block
289 K-code in a Shelby GT350
Overview
Manufacturer	Ford Motor Company
Also called	Windsor V8 Challenger V8[1]
Production	July 1961 – 2002
Layout
Configuration	Naturally aspirated 90° V8
Displacement	221 cu in (3.6 L) 255 cu in (4.2 L) 260 cu in (4.3 L) 289 cu in (4.7 L) 302 cu in (4.9 L) 351 cu in (5.8 L)
Cylinder bore	4.000" (289, 302, 351W) 3.800" (260) 3.680" (255) 3.500" (221)
Piston stroke	3.500" (351W) 3.000" (302 & 255) 2.870" (221, 260, 289)
Cylinder block material	Cast iron Deck height: 9.480" (1969–70 351W) 9.503" (1971–96 351W) 8.201–8.210" (BOSS 302) 8.206" (221, 260, 289, 302)
Cylinder head material	Cast iron
Valvetrain	Pushrod OHV Cast iron cam, Flat tappet (1962–84 302, 1969–93 351W) Steel roller cam & lifters (1985–2001 302, 1994–97 351W)
Compression ratio	9.0:1, 9.5:1, 10.5:1, 8.8:1, 8:1
Combustion
Fuel system	Carbureted (1962-1985 302, 1969-1991 351W) EFI (1988-1997 351W, 1986-2001 all others)
Fuel type	87 Octane
Oil system	Wet sump
Cooling system	Water-cooled; jacketed block
Output
Power output	115–310 hp (86–231 kW)
Torque output	262–385 lb⋅ft (355–522 N⋅m)
Dimensions
Length	27.50" (302, 351W) [lower-alpha 1]
Width	21.00" (351W) 18.75" (302)
Height	23.75" (351W) [lower-alpha 2] 20.75" (302)
Chronology
Predecessor	Ford Y-block engine
Successor	Ford Modular engine

Close

Designed as a successor to the Ford Y-block engine, it was first installed in the 1962 model year Ford Fairlane and Mercury Meteor. Originally produced with a displacement of 221 cu in (3.6 L), it eventually increased to 351 cu in (5.8 L), but was most commonly sold (from 1968–2000) with a displacement of 302 cu in (later marketed as 5.0 L).

This engine was installed in several of the company's most famous products, notably the Mustang, as well as the Mercury Cougar, Ford Torino, Ford Granada, Mercury Monarch, Ford LTD, Mercury Marquis, Ford Maverick, and Ford F-150 pickup.

For the 1991 model year, Ford began phasing in their new Modular V8 engine to replace the small-block, beginning with the Lincoln Town Car and continuing through the 1990s. The 2001 Explorer SUV was the last North American installation of the engine, and Ford Australia used it through 2002 in the Falcon and Fairlane.

Although sometimes called the "Windsor" by enthusiasts, Ford never used that designation for the engine line as a whole; it was only adopted well into its run to distinguish the 351 cu in (5.8 L) version from the 351 cu in (5.8 L) "Cleveland" version of the 335-family engine that had the same displacement but a significantly different configuration, and only ever used to refer to that specific engine in service materials. The designations for each were derived from the original locations of manufacture: Windsor, Ontario and Cleveland, Ohio.

From 1962 through the 1990s, these engines were marinized by various companies (except for the 255 cu in (4.2 L)).

The small block remains available for purchase from Ford Performance Parts as a crate engine.^[2]

The small-block engine was introduced in the 1962 Ford Fairlane and Mercury Meteor cars. Displacing 221 cu in (3.6 L), it was designed to save weight, using thin-wall casting with a block that does not extend below the centerline of the crankshaft. The engine uses a separate aluminum timing chain cover, which differentiates it from the later 335-series Cleveland engines that use an integrated timing cover. All Ford small-block engines use two-valve-per-cylinder heads, with "2V" and "4V" designations indicating the number of barrels (or venturi) in the carburetor. The valves are in-line and use straight six-bolt valve covers. Coolant is routed out of the block through the intake manifold.

The design was soon bored to 260 cu in (4.3 L) and again to 289 cu in (4.7 L), then stroked to 302 cu in (4.9 L), settling on the most common displacement offered until the engine's retirement in 2001, nearly 40 years after the basic block design debuted. Two additional displacements were produced during the engine's history. A 351 cu in (5.8 L) model was offered beginning in 1969 and continuing until 1996. The 351W (so identified to distinguish from the 335-series Cleveland 351C) uses a taller block than the other engines in the series to avoid excessively short connecting rods. And for a brief time in the early 1980s, a version with a smaller bore diameter that displaced 255 cubic inches (4.2 L) was produced as Ford struggled with emissions and fuel economy.

In response to the Chevrolet Camaro's success in the SCCA Trans-Am Series, Ford engineers developed a new racing engine from the small block. The first attempt mated a tunnel-port head to a 289 cu in block, but the displacement proved to be too small to deliver the desired power. The next iteration of the engine mated an improved head design to the 302 cu in block, producing the famous "Boss 302". The heads from the Boss 302 became the production heads on the 335-series Cleveland engines, which used the same bore spacing and head bolt configuration as the small block engines.

As the 1980s drew to a close, Ford began the design of a new OHC V8 to replace the venerable small block design. The Modular 4.6 L OHC V8 debuted in the 1991 Lincoln Town Car, signaling the eventual demise of the OHV Ford small-block. Through the rest of the decade, Ford gradually shifted V8 applications to the Modular engine, with the Mustang transitioning in 1996. Even as the small-block neared the end of its life, development continued, with new cylinder heads introduced for the Ford Explorer in 1997. American sales in new vehicles ended with the 2001 Ford Explorer, but the engine continues to be offered for sale as a crate engine from Ford Racing and Performance Parts.

The first engine of this family, called the Fairlane V8,^[1] introduced for the 1962 model year as an option on the Fairlane and Meteor, had a displacement of 221 cu in (3.6 L), from a 3.5 in (89 mm) bore and 2.87 in (72.9 mm) stroke, with wedge combustion chambers for superior breathing. An advanced, compact, thinwall-casting design, it was 24 in wide, 29 in long, and 27.5 in tall (610 mm × 737 mm × 699 mm). It weighed only 470 lb (210 kg) dry despite its cast iron construction, making it the lightest and most compact V8 engine of its type of the era.

In stock form, it used a two-barrel carburetor and a compression ratio of 8.7:1, allowing the use of regular rather than premium gasoline. Valve diameters were 1.59 in (40.4 mm) (intake) and 1.388 in (35.3 mm) (exhaust). Rated power and torque (SAE gross) were 145 hp (108 kW) at 4,400 rpm and 216 lb⋅ft (293 N⋅m) at 2,200 rpm.

The 221 was phased out end of May 1963 as a result of lackluster demand. About 371,000 had been produced.

The second version of the Fairlane V8 was given the name Challenger, and was introduced during the middle of the 1962 model year (March 1962).^[1] It had a larger bore of 3.80 in (96.5 mm), increasing displacement to 260 cu in (4.3 L). Compression ratio was raised fractionally to 8.8:1. The engine was slightly heavier than the 221, at 482 lb (219 kg). Rated power (still SAE gross) rose to 164 hp (122 kW) at 4400 rpm, with a peak torque of 258 lb⋅ft (350 N⋅m) at 2200 rpm.

For the 1962 and 1963 car model years, the valve head diameters remained the same as the 221, but for the 1964 car model year, they were enlarged to 1.67 in (42.4 mm) (intake) and 1.45 in (36.8 mm) (exhaust) – this was an economy measure so that both 260 and 289 engines could use the same valves. Rated power was not changed.

In 1963, the 260 became the base engine on full-sized Ford sedans. Later in the model year, its availability was expanded to the Ford Falcon and Mercury Comet. The early "1964½" Ford Mustang also offered the 260, although it was dropped at the end of the 1964 car model year.

Ford ceased production of the 260 at the end of the 1964 car model year with approximately 604,000 units having been made.

The 289 cu in (4.7 L) was also introduced in April 1963 and was also called the Challenger V8.^[1] Bore was expanded to 4.00 in (101.6 mm), becoming the standard bore for most small block engines. Stroke remained at 2.87 inches. The 289 weighed 506 lb (230 kg).

In 1963, the two-barrel 289 replaced the 260 as the base V8 for full-sized Fords.

The base version came with a two-barrel carburetor and 8.7:1 compression; it was rated at 195 hp (145 kW) (SAE gross) at 4,400 rpm and 285 lb⋅ft (386 N⋅m) at 2,200 rpm.

A high-performance version of the Challenger 289 engine^[1] was introduced late in the 1963 model year as a special order for Ford Fairlanes. The engine is informally known as the HiPo or the "K-code" (after the engine letter used in the VIN of cars so equipped). The engine was introduced in 1963 as the only 289 engine available in the intermediate Fairlanes. Lesser-powered cars had the 260 engine in that year. Starting in June 1964, it became an option for the Mustang.

The HiPo engine was engineered to increase performance and high-RPM reliability over standard 289 fare. It had solid lifters with hotter cam timing; 10.5:1 compression; a dual point, centrifugal advance distributor; smaller combustion chamber heads with cast spring cups and screw-in studs; low-restriction exhaust manifolds; and a bigger, manual-choke 595 CFM carburetor (the standard 289-4V was 480 CFM). The water pump, fuel pump, and alternator/generator pulleys were altered, fewer vanes, extra spring, and larger diameter, respectively; to help handle the higher engine speeds. Even the HiPo's fan was unique. Bottom-end improvements included a flaw-free selected standard block, thicker main bearing caps and crankshaft damper/balancer, larger-diameter rod bolts, a crankshaft made from 80% nodular iron as opposed to the regular items at 40%, all were checked for correct 'nodularity' by polishing an area of the rear counterweight and comparing that surface using a magnification arrangement against a picture datum, increased crankshaft counterweighting to compensate for the heavier connecting rod big ends, the increased external counter weighting at the front was split between the crankshaft damper and a supplementary counterweight place adjacent to the front main bearing journal (all designed to reduce the 'bending moment' in the crankshaft at high-rpm), all for high-rpm reliability. The HiPo equipped with a single 4-barrel Autolite 4100 carburetor carried SAE gross ratings of 271 bhp (275 PS; 202 kW) at 6,000 rpm and 312 lb⋅ft (423 N⋅m) at 3,400 rpm.^[5]

The K-code HiPo engine was an expensive option and its popularity was greatly diminished after the 390 and 428 big-block engines became available in the Mustang and Fairlane lines, which offered similar power (at the expense of greater weight) for far less cost.

Also, a 302 cu in 335-series engine 302 Cleveland was produced by Ford Australia for the Australian market.

By 1967, the Ford GT40 MKII and GT40 MKIV had dominated the Le Mans 24-Hour Race for two consecutive years, using various versions of the Ford big-block engine. In an attempt to reduce the high speeds, the organizers of this race capped the engine capacity in 1968. Ford consequently returned to the MKI GT40 (originally using the Windsor 289), but had now increased its capacity to meet the new rules. Since Ford had ruled that the GT40 engines must have a direct link back to its production cars, the 302 was adopted in domestic manufacturing.^{[citation needed]}

In 1968, the small-block Ford was stroked to 3 in (76.2 mm), giving a total displacement of 4,942 cc (4.9 L; 301.6 cu in). The connecting rods were shortened to allow the use of the same pistons as the 289. It replaced the 289 early in the 1968 model year.

The most common form of this engine used a two-barrel carburetor, initially with 9.5:1 compression. It had hydraulic lifters and valves of 1.773 in (45.0 mm) (intake) and 1.442 in (36.6 mm) (exhaust), and was rated (SAE gross) at 220 hp (164 kW) at 4,600 rpm and 300 lb⋅ft (407 N⋅m) at 2,600 rpm. Optional was a four-barrel version rated at 230 hp (172 kW) at 4,800 rpm.

The 302 was manufactured in Windsor from 1968 to 1978. Ten years of manufacture was punctuated by several design changes, some small or larger. In 1970, the manufacturing of the engine was moved from Windsor, Ontario, to Cleveland, Ohio. Along with the move came most changes that stayed with it for the remainder of its life. These were longer valve stems with rotating lash caps, bottle neck type rocker studs for a positive stop nut arrangement and a longer pushrod to correct valve train geometry. The water pump borrowed from the 351 Cleveland, with a few minor alterations to the casting, allowed the use of a left hand water inlet. (this improved water circulation in the radiator to a more cross-flow direction). This change also necessitated the need for a harmonic damper change to move the timing marks to the other side of the front timing cover and a change to four bolts holding the crank pulley rather than just three.

Emission regulations caused a progressive reduction in compression ratio for the 302 two-barrel, to 9.0:1 in 1972, reducing SAE gross horsepower to 210 hp (157 kW). In that year, U.S. automakers began to quote horsepower in SAE net ratings; the 302 two-barrel carried a net rating of 140 hp (104 kW). By 1975, its power had dropped as low as 122 hp (91 kW) in some models. Until fuel injection began to appear in the 1980s, net power ratings did not rise above 210 hp (157 kW).

From the 1978 model year, the 302 became more commonly known as the 5.0 Liter, although its metric displacement is 4,942 cc (4.9 L; 301.6 cu in). Ford may have used the "5.0" moniker to distinguish the 302 from their 300 cu in (4.9 L) inline six, which was known as the 4.9. Despite its advertised displacement, Car and Driver referred to the 302 as a 4.9-liter engine, though in common usage it is typically called a "5-Oh," "5-Point-Oh," "5 Liter," or "302."

Throttle-body fuel injection became available on the 1980 Lincoln Continental, and became standard on all non-H.O. 5.0 engines for 1983. For the 1986 model year, Ford replaced the throttle-body system with sequential multi-port fuel injection, identifiable by the large intake with an "EFI 5.0" badge on top.

In the late 1970s, an urgent need to meet EPA CAFE standards led to the creation of the 255 cu in (4.2 L) version for the 1980 model year, essentially a 302 with the cylinder bores reduced to 3.68 in (93.5 mm). The 302 was to be phased out and the 255 was to be an interim engine which would remain until the new V6 was in production. Rated power (SAE net) was 115–122 hp (86-91 kW), depending on year and application. Cylinder heads, which were specific to this engine, used smaller combustion chambers and valves, and the intake ports were oval whereas the others were all rectangular. The only externally visible clue was the use of an open-runner intake manifold with a stamped-steel lifter valley cover attached to its underside, reminiscent of previous-generation V8 engines, such as the Y-block and the MEL.

It was optional in Fox-chassis cars including the Mustang (and corporate cousin Mercury Capri), Thunderbird, and Fairmont, and standard equipment in the Ford LTD. Some variants (such as the one used in the Mercury Grand Marquis) were fitted with a variable-venturi carburetor which were capable of highway fuel economy in excess of 27 MPG. Due to its dismal overall performance, the 255 was dropped at the end the 1982 model year with 253,000 units manufactured; however, 302 production continued and the plans to phase it out were dropped.

Applications:

• 1980–1981 Ford Fairmont
• 1981–1982 Ford F-100
• 1981–1982 Ford Granada
• 1981–1982 Ford LTD
• 1980–1982 Ford Mustang
• 1980–1982 Ford Thunderbird
• 1980–1982 Mercury Capri
• 1980–1982 Mercury Cougar
• 1981–1982 Mercury Marquis
• 1980–1981 Mercury Zephyr

The 1982 model year brought a new 5.0 High Output variation. Manual-transmission equipped Mustangs and Mercury Capris were first equipped with two-barrel carburetors (1982), then a four-barrel Holley carburetor (1983–85). The block was fitted with revised, taller lifter bosses to accept roller lifters, and a steel camshaft in 1985, and electronic sequential fuel injection was introduced in 1986. While sequential injection was used on the Mustang beginning in 1986, many other vehicles, including trucks, continued to use a batch-fire fuel injection system. The speed-density based EFI systems used a large, two-piece, cast-aluminum manifold. It was fitted on all engines through 1988, after which year it was phased out for a mass air type measuring system in most applications (non–California compliant Panther platform cars retained the speed-density system until the Lincoln Town Car received the Modular V8 for model year 1991, and the Crown Victoria and Grand Marquis for 1992).

The same manifold was used in MAF applications, with the addition of the MAF sensor in the air intake tube. The MAF system continued, with minor revisions, until the retirement of the engine in 2001. Ford offered a performance head that was a stock part on 1993–1995 Mustang Cobra models and pre-1997 ½ Ford Explorers and Mercury Mountaineers equipped with the 5.0 L engine called the GT-40 head (casting ID F3ZE-AA). In mid-1997, the Explorer and Mountaineer 5.0 L heads were revised and renamed GT40P. The GT40P heads, unlike the GT40 heads, had a very well-developed port shape/design which yielded about 200 cfm on the intake side and 140 cfm on the exhaust side without increasing the size of the ports at all from standard E7TE castings, and without increasing the exhaust valve size. They also had smaller 59–61 cc combustion chambers for added compression, and the combustion chamber shape was revised to put the spark plug tip near the center of the chamber for a more even burn. These GT40P heads are considered by many enthusiasts to be extremely efficient.

The 302 remained a mainstay of various Ford cars and trucks through the late 1990s, although it was progressively replaced by the 4.6 L Modular engine starting in the early 1990s. The last 302 engine was produced for installation in a production vehicle at Cleveland Engine Plant #1 in December 2000, as part of a build-ahead to supply Ford of Australia, which installed their last such engine in a new vehicle in August 2002. The 302 is still available as a complete crate motor from Ford Racing Performance Parts.

Applications:

• 1982–1995 Ford Mustang
• 1982–1986 Mercury Capri
• 1984–1985 Ford Sierra XR8 (South Africa)^[9]
• 1987–1992 Lincoln Mark VII (1987 LSC models only)
• 1991–1993 Ford Thunderbird
• 1991–1993 Mercury Cougar
• 1991–2002 Ford Falcon
• 1991–2002 Ford Fairlane/Ford LTD
• 1996–2001 Ford Explorer
• 1997–2001 Mercury Mountaineer
• 1990–1996 Panoz Roadster

The 351W (Windsor) is often confused with the 351 Cleveland, which is a different engine of identical displacement. The 351.9 cu in (5.8 L; 5,766 cc) Windsor featured a 1.3 in (32.5 mm) taller deck height than the 302, allowing a stroke of 3.5 in (88.9 mm). Although very much related in general configuration to the 289 and 302, in that they share the same bellhousing, motor mounts, and other small parts, the 351W had a unique tall-deck block, larger main bearing caps, thicker and longer connecting rods, and a distinct firing order (1-3-7-2-6-5-4-8 versus the usual 1-5-4-2-6-3-7-8, a means to move the unacceptable "noise" of the consecutively-firing adjacent front cylinders to the sturdier rear part of the engine block all while reducing excessive main bearing load), adding some 25 lb (11 kg) to the engine's dry weight. The distributor is slightly different, so as to accommodate a larger oil pump shaft and larger oil pump. Some years had threaded dipstick tubes.

It had a unique head which optimized torque over high-rpm breathing, frequently replaced by enthusiasts with aftermarket heads providing better performance. The early 1969 and 1970 heads had larger valves and ports for better performance. The head castings and valve head sizes from 1969 to 1976 were different, notably in passages for air injection and spark plug diameters (1969–1974 18 mm, 1975 and up 14 mm). From 1977 onward, the 351W shared the same head casting as the 302, differing only in bolt hole diameters (7/16 inch for the 302, 1/2 inch for the 351W). Early blocks (casting ID C9OE-6015-B) had enough metal on bearing saddles 2, 3, and 4 for four-bolt mains, and as with all small-block Fords (SBFs), were superior in strength to most late-model, lightweight castings. Generally, the 1969 to 1974 blocks are considered to be far superior in strength than the later blocks, making these early units some of the strongest and most desirable in the entire SBF engine family including the 335-series. During the 1980s, a four-barrel version (intake manifold casting ID E6TE-9425-B) was reintroduced for use in light trucks and vans. In 1988, fuel injection replaced the four-barrel carburetor. Roller camshaft/lifters were introduced in this engine in 1994.

The original connecting rod beam (forging ID C9OE-A) featured drilled oil squirt bosses to lubricate the piston pin and cylinder bore and rectangular-head rod bolts mounted on broached shoulders. A number of fatigue failures were attributed to the machining of the part, so the bolt head area was spot-faced to retain metal in the critical area, requiring the use of 'football head' bolts. In 1975, the beam forging (D6OE-AA) was updated with more metal in the bolt-head area. The oil squirt bosses were drilled for use in export engines, where the quality of accessible lubricants was questionable. The rod cap forging remained the same on both units (part ID C9OE-A). In 1982, the design of the Essex V6 engine used a new version of the 351W connecting rod (E2AE-A), the difference between the two parts was that the V6 and V8 units were machined in metric and SAE units, respectively. The cap featured a longer boss for balancing than the original design.

The block underwent some changes since its inception. In 1971, deck height was extended from 9.480 in to 9.503 in (casting D1AE-6015-DA) to lower the compression ratio to reduce NOx emissions without the need to change piston or cylinder-head design. In 1974, a boss was added on the front of the right cylinder bank to mount the air injection pump (casting D4AE-A). In 1974, the oil dipstick tube moved from the timing case to the skirt under the left cylinder bank near the rear of the casting. These details made swapping older blocks from passenger cars with front sump oil pans to more recent rear-sumped Mustang and LTD/Crown Vic Ford cars more difficult unless an oil pan had the dipstick mounted therein. In 1984, the rear main seal was changed from a two-piece component to a one-piece design.

Introduced in 1969, it was initially rated (SAE gross) at 250 hp (186 kW) with a two-barrel carburetor or 290 hp (216 kW) with a four-barrel. When Ford switched to net power ratings in 1972, it was rated at 153 to 161 hp (114 to 120 kW), although actual, installed horsepower was only fractionally lower than in 1971. Around 8.6 million 351W engines were manufactured between 1969 and 1996 at the Windsor Engine Plant Number One.

During the 1990s, motor enthusiasts were modifying 351 Cleveland 2V cylinder heads (by rerouting the coolant exit from the block surfaces to the intake manifold surfaces) for use in the 351W, resulting in the Clevor (combining Cleveland and Windsor). This modification required the use of custom pistons by reason of differing combustion chamber terrain (canted valves vs. straight valves) and intake manifolds. This combination yielded the horsepower potential of the 351C with the ruggedness of the 351W small block and was possible because more 351C 2V cylinder heads were manufactured than the corresponding engine blocks (the 351M and 400 used the same head as the 351C 2V).

The 5.8 L, 351W, was changed during the 1990s from speed density to MAF; performance gains were directly affected. Before 1994, the 5.8 L was equipped with speed density. This programmed coding was placed into the vehicle's computer to tell the motor how much air it should be getting, therefore supplying an appropriate amount of fuel. However, if modifications are made to increase air flow, the computer does not provide more fuel until the oxygen sensors register a lean burn and only then can the computer compensate fuel trim. After 1994, the engine was changed to mass air flow (MAF). This allowed the computer to directly read how much air the engine was receiving through the help of a sensor in the air intake as long as that exact sensor was used (MAF sensors cannot be upgraded for increased flow without using an aftermarket chip or ECU). The rest of the intake system can be modified in any number of ways, but generally the MAF sensor remains stock. Because the computer reads this, it is able to increase the amount of fuel the engine gets when the air flow is increased, thus increasing performance.

Applications:

• 1969–1974 Ford Galaxie
• 1969–1970 Ford Mustang
• 1969–1971 Mercury Cougar
• 1969–1991 Ford Country Squire
• 1969–1970 Ford Fairlane (Americas)
• 1970–1976 Ford Torino
• 1974–1976 Ford Elite
• 1975–1996 Ford E series
• 1977–1979 Ford LTD II
• 1977–1979 Ford Thunderbird
• 1979–1996 Ford Bronco
• 1979–1982 Ford LTD (Americas)
• 1979–1991 Ford LTD Crown Victoria (after 1982, this engine would only be sold for police sales in the U.S.)
• 1987–1997 Ford F-Series
• 1977–1979 Mercury Cougar (station wagons only)
• 1978, 1986–1991 Mercury Colony Park
• 1978–1982 Mercury Marquis
• 1986–1991 Mercury Grand Marquis
• 1980 Continental Mark VI
• 1995 Ford Mustang SVT Cobra R

In the 2000s, Ford Racing Performance Parts sold two "Boss" crate engines and at least a 351 block. Most Ford racing versions of the 302 and 351 feature a siamesed bore and many of them feature drilled coolant crossover holes.^{[13][14][15][16][17][18]}

• List of Ford engines