Ford 335 engine
The
Ford 335 engine family were a group of
small-block V8 engines built by the
Ford Motor Company between
1970 and
1982. The series was nicknamed
Cleveland after the
Cleveland, Ohio engine plant in which most were cast. The 335 was designed as a mid-sized engine to replace the larger members of the
Windsor small-block family as well as the mid-sized
FE V8 family. Both of these engine families continued in production, however, with the Cleveland only outliving the FE by a half-decade and eventually abandoned in favor of the more compact Windsor design.
See also Ford Boss 351 engineThe
351 Cleveland was introduced in
1970 as Ford's new muscle car engine. It was built through the end of the
1974 model year. It incorporated elements learned on the
Ford 385 engine series and on the
Ford Boss 302 engine, particularly the poly-angle combustion chambers with canted valves and the thin-wall casting technology. Both a 4V (4-barrel carburetor) performance version and a 2V (2-barrel carburetor) basic version were built. The latter had a cylinder head with smaller valves, smaller ports, and open combustion chambers to suit its intended applications. The 351 Cleveland was produced through the
1974 model year (although it remained in production considerably longer in Australia), when Ford decided to economize and use the same block for both 351 and 400 cubic inch (5.8 and 6.6 L) applications. Only the Q-code 351 "Cobra Jet" (1971-73), R-code "Boss" 351 (1971), and R-code 351 "HO" (1972) versions have 4-bolt mains although all 335 series engines (351C/351M/400M) have space for them even in 2-bolt main form. The main difference between 351W/351C/351M/400M engines is connecting rod length and main bearing size. The 351/400M engines have the largest bearing size and the tallest deck height while sharing the 460 bellhousing pattern. The 351C engine has a medium main bearing size and shorter connecting rods than the 351W and the 351/400M while retaining the SBF bellhousing pattern. All of the 351C and 351/400M engines differ from the 302/351W by having an integrated timing cover casting in the front of the block. The 400M engine has the longest stroke of any SBF or 335 series engine.
Nominal main bearing sizes: 351M/400: 3.000 351C: 2.749Rod Length: 351M/400: 6.58 351C: 5.78Deck Height: 351M/400: 10.297 351C: 9.206
This engine was built only in Australia, and was intended to give their consumers a five liter alternative to the 351 Cleveland as the Ford "Windsor" series of engines was not commonly available there. Utilizing a locally produced 351 Cleveland block, 302 cubic inches (4.9 L) was attained by reducing the stroke of the 351C from 3.5 to 3 inches (89 to 76 mm). Additionally, the 302C cylinder heads were designed locally, with smaller combustion chamber to compensate for the reduced stroke of the engine. This combination of closed combustion chambered quench heads with smaller 2 barrel style ports made a more powerful setup known in the USA as "Australian heads". These heads interchange directly onto 351C engines, and are highly sought outside of Australia as a low-cost method to increase compression ratio. They are a good street alternative to the over ported 4 barrel heads.
Note: Using the 302C cylinder heads on an otherwise unmodified 351C will increase the compression ratio beyond a safe level for regular pump fuel. Using the small chamber 302C cylinder heads properly requires engine design changes (deck clearance, piston design, cam shaft specifications) optimized for the intended use
The
big-block FE engine family was getting rather tired and outdated, and the
385 family could not meet the efficiency requirements of the time. At the same time, the small-block
Windsor engines were too small and high-revving for Ford's
fullsize car and truck applications. So the company went to work on a new small-block to meet the desired levels of economy while still providing the kind of big-block torque that was needed to move 2+ ton vehicles.
The Ford
400 engine had "
square" proportions, with a 4.0 in (102 mm) bore and stroke; it therefore
displaced 402 in³ (6.6 L), making it the largest
small-block V8 made at that time. It was introduced in
model year 1971 with a full half-inch (13 mm) longer stroke than the 351 Cleveland, making it the longest-stroke Ford
pushrod V8 engine. A long-stroke engine has good low-end torque, for which it trades high-end power. This was a good compromise given Ford's requirement for an engine to power heavier mid-size and full-size cars and light trucks. The M-block, as it became known, was the last pushrod V8 block designed by Ford, and it had a deck height over an inch (25 mm) higher than the Cleveland. The M-block does share one element with the Windsor family: it has large 3.00 inch main journals.
The 400 was seen as a smaller and lighter replacement for the big
Ford 385 engines, the 429 and 460, in Ford's big cars. Weighing just 80% of a similar big block, it was originally available in Ford's
Custom,
Galaxie and
LTD lines, and in
Mercury's
Monterey,
Marquis, and
Brougham. Later, it would power the
Ford Thunderbird, the
Lincoln Continental, and
Mark V.
The 400 uses the same
bellhousing bolt pattern as the
385 family big-block to make it compatible with the higher torque-capacity
C6 transmission used on the large cars and trucks. Exception: There is a 400 block casting that uses a "small block" pattern on the rear for mounting an FMX transmission. These castings are rare. The 400 was modified in
1975 to use
unleaded gasoline.
When the 351 Cleveland was withdrawn after the end of the
1974 model year, Ford needed another engine in the 351 cubic inch (5.8 L) class, since production of the
351 Windsor was not sufficient and the
390 FE was being retired as well. To replace the 390, Ford took the 400 engine's tall-deck block and de-stroked it, with a shorter throw
crankshaft and taller
pistons, to produce a 351 cubic inch (5.8 L) engine whose components were largely compatible with the 400. This engine was called the
351M and as a back-formation the taller-deck block became known as the
M-block. These engines were built in Cleveland, and the performance reputation of the 351 Cleveland engine was such that the company continued to refer to "351 Cleveland" in marketing for a couple years after the change.
For the
1977 model year, Ford decided to replace its ageing
FE big-block 360 and 390 engines in its light truck line with its new 351M and 400 engines. For light truck use, beefed-up blocks were designed. These enhancements were added to all M-block engines starting with the
1978 model year.
1979 was the final year the M-block engines were used in cars. After that, the
Ford 351 Windsor at 5.8 L was the only large car engine used. Reduced demand for large engines due to fuel economy regulations led to the abandoment of the Cleveland production line that produced the 351M and 400 engines.
The M-block engine was designed when first-generation pollution controls were already in place in the United States, and the engine was designed to support the Thermactor
air injection reaction (AIR) and
exhaust gas recirculation (EGR) systems internally inside the block and heads. Previous engine designs required bulky and unsightly external tubing to feed Thermactor air into the exhaust manifolds and exhaust gas to the EGR valve below the
carburetor, but this was all built in to the M-block engine.
This all made adapting the M-block to the second generation of emissions control equipment harder. One requirement of the second-generation equipment was an O
2 sensor in the exhaust, which had to be placed before the Thermactor air was added. Since Thermactor air was injected right into the block's exhaust ports in the M-block, there was nowhere for the O
2 sensor to go.
It would have been possible to alter the M-block to work, but it would have required significant effort. Ford decided to simply scrap the M-block engines and replace them with updated 351 Windsor engines at the small end, and a combination of the 6.9 L
Navistar diesel and the 460 at the top end. 1982 was the last year the M-block was sold.
*
Ford 385 engine*
List of Ford engines*
Short descriptions of Ford overhead valve V8 engines*
M-Block Ford V8 Workshop
