ENGINES

Ford offered Cobra Jet and Super Cobra Jet versions of the 429. The Cobra Jet, rated at 370 hp, was equipped with a Rochester Quadrajet carburetor, larger camshaft, 11.3 to 1 compression ratio and a special set of cylinder heads. The Super Cobra Jet, rated at 375 hp, had a 4-bolt main block, a Holley carburetor, and a larger mechanical camshaft. In 1971, the CJ engine also used a 4-bolt main block. However, these engines were actually underrated and produce power in the 440-460 hp range. This was done to deceive insurance companies (common practice in that era), so that buyers did not have to pay higher insurance rates.

The 351 Cleveland was introduced in 1969 as Ford's new performance car engine and was built through the end of the 1974 model year. It incorporated elements learned on the 385 big-block series and the Boss 302, 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, both with 2 valves per cylinder. The latter had a different cylinder head with smaller valves, smaller ports, and open combustion chambers to suit its intended applications.
Only the Q-code 351 "Cobra Jet" (1971-1974), R-code "Boss" 351 (1971), and R-code 351 "HO" (1972) versions have 4-bolt mains although all 335 series engines (351C/351M/400) have space for them even in 2-bolt main form. The main difference between 351W/351C/351M/400 engines is connecting rod length and main bearing size. The 351M/400 engines have the largest bearing size and the tallest deck height while sharing the 429/460 bell housing pattern. The 351C engine has a medium main bearing size and shorter connecting rods than the 351W and the 351M/400 while retaining the SBF engine mount locations and bell housing pattern. The 400 engine has the longest stroke of any SBF or 335 series engine.
All of the 351C and 351M/400 engines differ from the 302/351W by having an integrated timing cover casting in the front of the block to which the radiator hose connects.

H-code

1973 H-code 2V 351 Cleveland
The majority of 351 Cleveland engines are H-code 2V (2-venturi carburetor) versions with low compression. These were produced from 1970 through 1974 and were used on a variety of Ford models from compact to intermediate.

M-code
The M-code version was produced from 1970 through 1971. Both years offered quench heads but 1970 offered a slightly higher (advertised) 11.4:1 compression ratio whereas in 1971 the chamber was opened up slightly reducing the advertised compression to 10.7:1. The 1970 4V head is identified with the proper date code casting and a "4" cast on the upper corner of the head. The 1971 4V head is identified with a "4*" (four-dot) casting at the same location. Hydraulic lifters were also specified, with the M-code producing about 300 hp (224 kW). 2-bolt main caps were used along with a cheaper cast iron intake manifold.

1971 R-code (Boss 351)

The 1971 R-code "Boss 351" used higher compression (11.7:1) with the quench head 4V heads, solid lifters, an aluminum intake manifold, and 4-bolt main caps. It produced about 330 hp (246 kW).

1972 R-code
The R-code 351 Cleveland for 1972 was considerably different. It had reduced compression for emissions compliance and used open-chamber heads. It had a Hydraulic camshaft, however a four barrel carburetor was retained. It produced 400 hp (207 kW) using the new SAE net system.

Q-code (Cobra-Jet)
The Q-code "351 Cobra Jet" version was produced from May 1971 through the 1974 model year. It was a low-compression design that included open-chamber "4V" heads, a special intake manifold, special hi-lift long duration hydraulic camshaft, special valve springs and dampers, a 750 CFM 4300-D Motorcraft Carburetor, dual-point distributor, and 4-bolt main bearing caps. It was rated at 266 hp (198 kW) (SAE net) for 1972 when installed in the [[Ford MustangMustang] and 248 hp in the Ford Torino and Mercury Montego. The rating remained 266 hp for the Mustang and dropped to 246 hp (183 kW) for the intermediate Ford and Mercurys for 1973. The 351 CJ was rated at 255 hp in 1974 and was only installed in the Ford Torino, Mercury Montego and the Mercury Cougar.

302 Cleveland
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 in³ (5.0 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. 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.

400
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 was based on the 351 Cleveland but was produced with a 1 inch taller deck height to allow for a crankshaft with a longer stroke. The 400 also featured larger main-bearing journals and 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 (12.7 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. 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 later became known, was the last pushrod V8 block designed by Ford. The M-block also shares some elements with the Windsor engine family: bore spacing, cylinder head bolt-patterns and crankshaft journal dimensions.
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, Mark V, mid-size Fords and Mercurys, and Ford light-duty trucks.
The vast majority of 400 blocks use 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. There were a small number of 400 block castings that use 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.

351 M
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 the shorter throw crankshaft from the 351 Windsor, 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.

VECHILES

in 1967 A convertible prototype of the GT500 was made, which was suppose to be scrapped. but Before Ford Motor Company could destroy the prototype, it was stolen. The car was eventually recovered by Ford and sold as '68.