Ford 335 engine

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Ford 335 V8
1969 Ford Mustang 351 Cleveland.JPG
Manufacturer Ford Motor Company
Also called Ford Cleveland V8
Production 1969–1982
Combustion chamber
Configuration 90° OHV small-block V8
4.380" bore spacing
Displacement 302 in3 (5 L)
351 in3 (5.8 L)
400 in3 (6.6 L)
Cylinder bore 4.0 in (102 mm)
Piston stroke 3.0 in (76 mm)
3.5 in (89 mm)
4.0 in (102 mm)
Cylinder block alloy Cast Iron

Deck Height:
9.206" (302C, 351C)
10.297" (351M, 400)
Cylinder head alloy Cast Iron
Valvetrain Overhead valve
Cast iron cam, Flat tappet
Predecessor Ford FE V8
Ford Windsor V8
Successor Ford Windsor V8

The Ford 335 engine family was a group of small-block V8 engines built by the Ford Motor Company between 1969 (for the 1970 model year) and 1982. The significance of the numerals '335' designated to this series of Ford V8 engines came from Ford management who dictated 335 cu in be the original capacity with room for expansion during its development.[1] This engine family began production in late 1969 with a 351 cu in (5.8 L) engine, commonly called the 351C. It later expanded to include a 400 cu in (6.6 L) engine which used a taller version of the engine block, commonly referred to as a tall deck engine block, a 351 cu in (5.8 L) tall deck variant, called the 351M and a 302 cu in (4.9 L) engine which was exclusive to Australia.

The 351C, introduced in 1969 for 1970 model year, is commonly referred to as the 351Cleveland after the Cleveland Engine plant in which most of these engines were manufactured. This plant complex in Brookpark, Ohio, included a gray iron foundry (casting plant), a stamping plant, and an engine assembly plant. As newer automobile engines began incorporating aluminum blocks, Ford eventually closed the casting plant in May 2012.[2] The 335 series engines were used in mid-sized and full-sized cars, as well as light trucks, (351M/400 only) at times concurrently with the larger member of the Windsor small-block family, the 351 Windsor, in cars. These engines were also used as a replacement for the FE V8 family in both the car and truck lines. The 335 series V8 engines, only outliving the FE by a half-decade, were eventually abandoned in favor of the more compact Windsor V8 engines.


The 335 series V8 engines were introduced in late 1969 as the 351C. In the third quarter of 1970, the 400 was introduced to the passenger car lines, while the 351M replaced the 351C for the 1975 model year.[3] Ford of Australia built the 351C engine beginning in November 1971, which was very similar to the American counterpart. Alongside the 351C, the 302C engine was produced which was exclusive to the Australian market.[1] The 335 series V8s were overhead valve pushrod V8 engines that used a short-skirt engine block. This family of engines incorporated elements learned on the 385 big-block series, particularly the poly-angle combustion chambers with canted valves, and thin-wall casting technology. All 335 series V8s all had free breathing, large-port canted valve heads with a rugged engine block.[4] The 335 engines use large main-bearing caps, with four-bolt attachment on some versions of the engines. All 335 series engines are cast with provisions for four-bolt main bearing caps to be added through modification.[4]


Comparison to Ford Windsor V8[edit]

All 335 Series V8s shared the same 4.38 in (111 mm) bore spacing and cylinder head bolt pattern as the Windsor V8s. Beyond these shared aspects, the 335 Series engines are very different internally from the somewhat similar-looking Windsor series. The 335 series V8s use smaller 14mm spark plugs and the radiator hose locations differ between the Windsor and 335 engines. The Windsor engines route coolant through the intake manifold, with the hose protruding horizontally, while the 335 engines had a dry manifold with the radiator hose connecting vertically to the cylinder block above the cam timing chain cover. The Cleveland has a square-shaped rocker cover while the Windsor has a more rounded cover. All 335 covers are secured with eight bolts; the Windsor uses six bolts. All of the 335 series engines differ from the Windsor engines by having a roughly 2-inch extension at the front of the block which forms an integrated timing cover casting.

Oil system differences[edit]

As a method to reduce production costs, Ford eliminated one of the main oil galleys from the block casting, resulting in the 335 series having two galleys versus the Windsor family's three galleys.[5] The result was an oil system very similar to the 385 series V8 engines. The two main oil galleys in the 335 series engine run along the lifter bores. Oil is fed from the filter to the number one main bearing followed by the number one cam bearing above. At the same time, it also feeds the right hand oil galley, feeding the right side lifter bank. The lifter bank has four galleys that lead to each of the remaining main bearings. After the oil feeds the main bearings, it feeds each corresponding camshaft bearing above. At the rear-most main bearing, the oil goes into the other galley which feeds the left lifter bank.[1][6] This system has proven to be adequate for street engines, but can fall short in high-revolution race use without modification.[5]

Cleveland block                         VS
Windsor Block

Cylinder heads[edit]

The cylinder head design for the 335 series engines is its most definitive aspect. All cylinder heads were two-valve heads that use large ports with poly-angle or 'canted' valves.[4] This resulted in the intake and exhaust valves being at separate angles. Canting the valves allowed for very large valves to be installed, while reducing the port length and minimizing sharp turns within the port.[7] The end result was a cylinder head that had valves and ports much larger and freer flowing than the Ford Windsor V8s, and in some cases larger than some of the Ford FE and 385 Series V8s.[8] This same basic cylinder head design was used on the Ford Boss 302 engine, after it was modified to work with the Windsor engine block.[1] Most 335 series engines used stamped rocker arms with cast fulcrums that made for a nonadjustable valve train. Only the Boss 351 and 351 HO had adjustable valve train which had rocker arms mounted on screw-in studs and used guide plates.[1][9]

The 335 series engines used one of two different cylinder heads. The 4V head was used on engines equipped with a four-barrel carburetor (four venturis) while the 2V head was used with the engines equipped with two-barrel carburetors (two venturis). The 4V heads had larger ports and valves than the 2V, but the 2V heads still had ports and valves that were significantly larger than Windsor engines.[8] The 4V head's large ports and valves were designed to promote better breathing at high rpm, while the smaller 2V ports have proven to be better for street use.[10] The cylinder heads used either an open, almost shallow hemispherical combustion chamber or a closed "quench" type combustion chamber. The closed chamber heads enclose the valves more closely, reducing the combustion chamber volume, but both combustion chamber designs have the same thermal efficiency and resistance to detonation.[7] The closed combustion chamber promotes a better swirling action of the incoming air fuel mixture which provides a low-rpm torque advantage over the open chamber. However, the open chamber cylinder heads exhibit better emissions characteristics.[1] The other significant advantage to the closed chamber heads is that less machining is required to obtain high compression ratios.[7]

335 Series V8 Engine Cylinder Heads[1][4][8]

351 Cleveland[edit]


Production of the 351 Windsor V8 engine began for the 1970 model year in the Windsor Engine Plant #1. Ford sales and marketing forecast that the demand for this engine would exceed the plant's production capability, and it was decided the additional production would begin at the Cleveland engine plant. At this time, it was also decided to upgrade the engine to a higher-specification power plant.[1] Two cylinder-head designs were developed to improve the 351W head. One cylinder head used the same basic design as the 351W, but with larger ports and valves; the other had canted intake and exhaust valves, similar to the Ford 385 Series V8. Sales, marketing, and product planning favored the canted valve design, as it was viewed as more innovative.[1]


The 351 Cleveland was introduced in 1969 for the 1970 model year. Its actual displacement was 351.9 cubic inches (5,766 cc). A 4V performance version and a 2V version were built. The 351C-4V was marketed as a high-performance engine, featuring large valves and ports and a closed "quench" combustion chamber. Later versions of the 351C with 4V heads continued to use the large ports and valves, but switched to open chamber heads in an effort to reduce engine emissions. The 351C-2V was not marketed as a high-performance engine. It used the 2V cylinder heads with smaller valves, smaller ports, and open combustion chambers to produce a more economical engine that produced greater low-rpm torque.[4] Only the Q-code 351 "Cobra Jet" (1971–1974), R-code "Boss" 351 (1971), and R-code 351 "HO" (1972) versions have four-bolt main bearing caps.[4]


1973 H-code 2V 351 Cleveland

The H-code 351 Cleveland engines are two-barrel carburetor 351Cs with lower compression. Compression ratio ranged from 9.5:1 in 1970 to 8.0:1 in 1973 and 1974 and all years ran on regular-grade fuel. All H-code 351's were equipped with a cast-iron crankshaft, two-bolt main bearing caps, forged-steel connecting rods, cast-aluminum pistons, nonadjustable valvetrain, and cast-iron intake and exhaust manifolds.[3] All H-code 351 Cleveland engines used the 2V heads with smaller ports and had open combustion chambers.[1] These engines were produced from 1970 through 1974 and were used on a variety of Ford models, from pony car to full-sized.[3] The 351W with a 2V carburetor was also produced during this time with the same horsepower rating, but Ford used the "H-code" to describe both engines.[11]


The M-code was a high-compression, high-performance variation of the 351C, produced in 1970 and 1971. The M-code engines used the large-port 4V heads with a closed "quench" combustion chamber and large valves.[3] These engines also included cast-aluminum flat-top pistons, stiffer valve springs, a high-performance hydraulic camshaft, and a squarebore Autolite 4300-A carburetor.[1] The 1970 engines were 11.0:1 compression and produced 300 bhp (224 kW; 304 PS) at 5400 rpm, while 1971 versions had a slightly lower compression ratio of 10.7:1, and produced 285 bhp (213 kW; 289 PS) at 5400 rpm.[3] The M-code 351C required premium fuel and was available in the 1970-71 Ford Torino, Mercury Montego, Ford Mustang, and Mercury Cougar.[11][12]

1971 R-code (Boss 351)[edit]



1972 R-code (351 HO)[edit]


Q-code (Cobra-Jet)[edit]

The Q-code "351 Cobra Jet" version was produced from May 1971 through the 1974 model year. It was a lower-compression design that included open-chamber 4V heads.[3] The open-chamber heads exhibited superior emissions characteristics and were required to meet the more stringent emissions standards for 1972 and beyond.[1] The "351 Cobra Jet" high-performance engine that included a different intake manifold, high-lift, long-duration camshaft with hydraulic valve lifters, different valve springs and dampers, a 750-CFM spread-bore 4300-D Motorcraft carburetor, dual-point distributor (with four-speed manual transmissions only), and four-bolt main bearing caps. These engines also featured induction-hardened exhaust seats for use with low-lead and unleaded gasoline.[3] This engine was different from the 1970-71 M-code 351C having a more aggressive camshaft, a spread-bore carburetor, a four-bolt block[14] and the lower compression allowed regular fuel to be used.[17] It was rated at 280 bhp (209 kW; 284 PS) for all 1971 applications. For the 1972 model year, the only change to the engine was a retarding the camshaft events by 4°.[1] The engine was rated at 266 hp (198 kW) (SAE net) for 1972 when installed in the Mustang, and 248 hp (185 kW) in the Torino and Montego.[3] An increase in the combustion chamber size and the use of smaller valves occurred in 1973,[1] which reduced horsepower to 246 hp (183 kW) for the four-barrel for the intermediate Fords, though it still retained the higher 266 hp (198 kW) rating in the Mustang.[3] The 351 CJ (now referred to as the "351 4V") was rated at 255 hp (190 kW) in 1974 and was only installed in the Ford Ranchero, Ford Torino, Mercury Montego, and Mercury Cougar.[13]


Production of the 351C ended at the end of the 1974 model year. The engine was replaced by the 351M for the 1975 model year. This new variation used the same bore and stroke dimensions of the 351C, but used the tall deck block from the 400 V8 engine.

351C engine specifications chart[edit]

351 Cleveland engines[1]

400 and 351M[edit]



The Ford 400 engine was based on the 351 Cleveland. It had a half-inch (12.7 mm) longer stroke than the 351 Cleveland, making it the longest-stroke Ford pushrod V8 engine. The 400 had "square" proportions, with a 4.0 in (102 mm) bore and stroke. Ford called the engine 400 cu in but it actually displaced 402 cu in (6.6 L), making it the largest displacement small-block V8 made at that time. The longer stroke required Ford to increase the block deck height to 10.297 inches compared to the 351C's 9.206 inches.[3] As a result, the 400 used longer (6.580 inch) connecting rods than the 351C (5.778 inch), but it retained the same connecting rod-to-stroke (1.65:1) ratio as the 351C.[1] The 400 featured larger 3.00 inch main-bearing journals, the same size as those used in the 351 Windsor, but rod journals were the same size as the 351C.[3] The cylinder heads for the 400 were the same as those used on the 351C-2V, having the open combustion chamber with smaller 2V sized ports and valves. The 400 was only ever produced with a 2-barrel carburetor, a cast-iron intake manifold, and the smaller port 2V cylinder heads.[3][21]





Engine dimensions[1]
351C 400 351M



Light truck usage[edit]


Block Cracking Problems[edit]


351M/400 identification confusion[edit]

There exists debate as to what Ford meant by the "M" designation of the 351M. Some claim the "M" stands for “Modified” - being modified from a 400-V8 with a shortened stroke - though others claim that the "M" refers to the Michigan Casting Center, where the 351M began production. Some say that the "M" designation has no official meaning, and that it was just Ford's way of distinguishing the 351M from the 351C and 351W.[28]

Likewise, Ford's use of the 400 block in the creation of the 351M engine has resulted in the 400 mistakenly being referred to as the "400M" or "400 Modified." This is despite the 400 having been the design basis from which the "modified" 351M was derived and it was in production several years before Ford used the "M" designation. Further confusion arises from Ford printing "351M/400" on the emission stickers for the engine. The "351M/400" referenced the engine family, and some confused this with the engine name. This sticker also listed the engine displacement below the engine family. Ford's official name for the 400 V8 contains no additional designations - the proper nomenclature is simply "400."




302 and 351 Cleveland (Australia)[edit]

Note that there was also a 302 "Windsor"




302 Cleveland[edit]




351 Cleveland[edit]


See also[edit]


  23. ^
  30. ^ Heitz, Rudolf, ed. (1 August 1986). Auto Katalog 1987 (in German). 30. Stuttgart: Vereinigte Motor-Verlage GmbH & Co. KG. p. 120. 

External links[edit]