No doubt about it, the single biggest component that gives a car its reason for being is the engine. Without it, a vehicle is nothing. And different engines, even in the same basic car transform its personality. Take the case of a four-cylinder Fox Mustang and a thumping 5.0 LX. They look the same on the outside, the same from behind the wheel, but when you touch the pedal, they respond in very different ways. Throughout the course of our favorite ponycar’s history, there have been a number of powerplants that have made a lasting impact, turning their hosts into revered machines. And whether big, thumping V8s or efficient turbo-charged fours, these engines and the Mustangs equipped with them have left an indelible mark on generations of owners, drivers and enthusiasts.
1. Ford 260/289 V8 Codenamed “Challenger,” this small V8 was the replacement for the old Y-block and originally designed for use in the mid-size Fairlane. It debuted in a 221 cubic inch guise back in early 1962 with a 3.5-inch bore and 2.48-inch stroke. It was enlarged to 260 cubic inches several months later via a bigger 2.5-inch bore. A high performance version with a four-barrel carburetor and aggressive cam, rated at 260 hp, was installed in Carroll Shelby’s lightweight Cobra sports cars, as well as race and rally prepped Ford Falcons. With a bigger 4.00-inch bore, the 260 became the 289, which supplanted its predecessor entirely by the end of 1964. With its oversquare design and compact exterior dimensions, the Challenger was an efficient engine in its day and adaptable to a wide variety of configurations. It could be had with an Autolite two-barrel carburetor, as were most installed in early Mustangs, or once enlarged to 289 cubic inches, could, as the C-code engine, be specified with a less restrictive intake manifold and a four-barrel carb, which improved breathing and fuel delivery, resulting in a power gain of approximately 25 hp. During 1964, the 289 block was modified slightly with a new bell housing and on the four-barrel version, revised pistons, which boosted compression and power from 210 to 225 hp.
Most exotic of all the 221/260/289 family is the so-called 289 High Performance variant, offered between 1964 and 1967 and labeled as the K-code engine. This shared the basic structure of the standard 289, but featured a stronger bottom end with bigger main bearing caps and rod bolts, a special high performance camshaft with more lift and increased duration, mechanical instead of hydraulic valve lifters and different heads and high performance exhaust manifolds, plus a dual point distributor. Outfitted with a 595 cfm four-barrel carburetor, it was designed to rev and made maximum power (271 hp) at a relatively high, for the time, 6,000 rpm. It was fairly high strung and required an experienced driver to really get the most out of it. Carroll Shelby installed versions of this engine in his ultra lightweight Cobras and souped up Mustangs. In the latter, the engine was tuned to deliver 306 hp, via carb rejetting, low restriction exhaust and modifications to the cylinder heads and intake manifold. For 1966, Shelby offered a Paxton ball drive supercharger as an option, resulting in well over 375 hp in street tune.
2. Ford 427 Conceived as a race only engine, the 427 was an outgrowth of the original FE (Ford Edsel) big block V8s, begun in 1958 with the 332 and 352 Thunderbird Special. It was designed to wage war on the dragstrip and stock car circuit, as a response to Chevrolet’s own version and the displacement was chosen because it was the largest legally possible within NASCAR rules at the time. Compared to other FE engines, the 427 had a stronger block with thicker castings on the cylinder walls and deck. All used a steel crankshaft and were fully balanced for ultra high performance use. Early versions were called top oilers due to the way in which oil was fed into the engine from the top of the block into the valvetrain and then the bottom end. However, this design could cause oil starvation at wide-open throttle, damaging the bottom end, so, beginning in 1965 a redesigned block with side lubing, which sent oil first to the crank and then to the cam and valvetrain was introduced. Known as the side oiler, it was this version that found its way into a select few 1967 Shelby GT500s and some regular ’68 Mustangs. The 427 remains one of the most revered Ford engines of all time and today is becoming increasingly popular again, thanks to a plethora of performance parts and replacement blocks being introduced.
3. Ford 302 A development of the original Challenger, the 302 featured the same stroke but a larger 4.00-inch bore than the 289. It was introduced primarily to satisfy pending emissions requirements and first appeared in Mustangs beginning with the 1968 model year. In its day, the 302 was remarkably efficient and its two-bolt main block and five-bearing crankshaft would prove almost indestructible. This engine also became one of the most versatile of Ford engines, and could be found in everything from pedestrian pickup trucks to high performance Shelby G.T. 350s, available with a variety of intake, carburetor and exhaust configurations, not to mention heads and valvetrains. The Shelby version was actually a one-year special that featured a stronger block with fortified main caps (the so called Mexican block, because it was built south of the border). It also featured a nodular cast crank, heavy-duty rods and special heads with unique valvetrain pieces, rocker arms and pushrods. Further Mexican block 302s were built after Shelby production ended, but without the high performance parts, though they were available well into the early ’80s, mostly in full-size pickups. The 302, in part due to its simplicity and ease of tune, proved to be ideally suited to competition and formed the basis for the much-revered Boss 302 Trans Am engine. It also ended up powering three generations of Ford vehicles, including countless Mustangs through the 1995 model year and became the chosen powerplant for thousands more kit cars and street rods.
It was Ford’s answer to the small-block Chevy and today remains a firm favorite with car enthusiasts around the world. In fact, demand for these engines is so strong that thousands of hop up parts are still available and a wide variety of manufacturers, including Ford Racing Performance Parts offer brand new ones as crate engines, in stock or stroked versions, for street or track.
4. Ford 428 Cobra Jet Ford’s trump card during the muscle car years, the 428 was the ultimate development of the FE (Ford-Edsel) line of big-block V8s. The Cobra Jet was based on the 428 or “7-Litre” designed for use in the big Fords, but featured a stronger block, stronger main and end caps, reinforced webbing and a high performance crankshaft, rods with floating pins. It also featured forged alloy 10.6:1 compression pistons to withstand extra high temperatures and cylinder heads borrowed from the low riser 427 with larger valves, ports and a performance intake manifold (actually a cast iron version of the aluminum police interceptor unit), topped by either a single 735 cfm Autolite four-barrel carburetor or a special manifold designed for twin in-line carbs, as was fitted to a number of Shelby Mustangs. Ford rated it at 335 hp, mainly for insurance reasons, but actual power was reputedly in the 400 hp range. Whatever the actual rating may have been, the 428 featured a fairly long stroke and was a torque monster, packing a walloping 450 lb-ft. Cars equipped with it were among the fastest and most tractable on both the street and track during the late ’60s and in racing, the CJ won nearly everything in sight. It was first available in Mustangs, beginning in February 1968 and would last through the 1970 model year, after which it was supplanted by a CJ version of the new 429. Besides the regular 428 Cobra Jet there was also an even stronger version, the Super Cobra Jet.
This featured a block with stronger main bolts, externally mounted oil cooler and unique moving parts, including Le Mans “competition” oriented heavy duty connecting rods, special nodular cast iron crankshaft, with externally mounted damper and unique forged pistons. It was rated at the same 335 hp as the “regular” CJ, but even beefier internals, making this version, the hardcore drag racer’s choice.
5. Boss 302 Perhaps the ultimate development of the Challenger V8, this was a very special engine, designed for Trans Am racing. Originally it was to be a very high winding 302 with a special tunnel port intake manifold and cylinder heads, though Ford ran into problems during development. Instead, it assembled the Boss 302, which featured a special four-bolt block, with thicker cylinder walls than other 302s plus screw in freeze plugs for maximum durability. It also forged steel crank, heavy duty rods, special forged aluminum 10.5:1 compression pistons and some exotic top end parts, including a pair of massive cylinder heads with huge canted valves and oversized ports, an aluminum high rise intake manifold and a huge 780 cfm Holley four-barrel carburetor and a high lift camshaft with mechanical lifters (that resulted in a real racket upon startup) plus an Autolite dual-point distributor with a very aggressive spark curve. As a result, it was a very peaky engine and didn’t come into its own until well above 4,000 rpm. Rated at 290 hp and 350 lb-ft of torque, it was hard work on the street, but on the track it was a screamer. Although it revved all the way up to 7 grand on the tachometer, in the interests of durability, Ford installed a 6,150 rpm electric rev limiter on the street version of this engine. The Boss 302 was offered in 1969-1970 Mustangs of the same name as well as the 1969-1970 Mercury Cougar Eliminator.
6. Boss 429 Probably the most exotic of all the Ford era muscle car engines was the infamous Boss 429, also known as the Semi Hemi, Blue Crescent, or Shotgun. It was based on the new 385 series 429 big-block, designed to replace the FE 428 in Ford’s range of large cars. The division decided to homologate a version of this new engine for NASCAR racing, but decided to offer a street version in a specially built 1969 Mustang fastback. The Boss 429 shared its block with the other 385 series engines, but featured a thicker casting, standard four-bolt mains, (on four of the five main crank bearings) with screwed in end caps, a cross-drilled steel crank, forged steel connecting rods and forged alloy pistons the size of dustbin lids.
It also featured a pair of massive canted valve aluminum heads, with huge valves and semi-hemispherical combustion chambers. The unique head design was conceived to promote faster, hotter burning in the chamber to improve power. Like the Boss 302, the Boss 429 was designed as a revver, so it employed a specially designed camshaft and initially hydraulic valve lifters (though these were changed to solid units and an even more aggressive cam specified during the course of 1969). The intake manifold was a special cast aluminum dual-plane piece with large ports to promote breathing and the carburetor was a Holley 735 cfm unit. The engine was so physically huge, that the Mustang’s shock towers had to be specially widened to accommodate it and a massive hoodscoop installed to clear the air cleaner. Although on paper, the Boss 429 had all the right credentials as an ultra-high performance engine, it never garnered much of a reputation on the street. The high lift cam and huge ports meant that it needed to be spun to really come into its own and many would-be buyers preferred the effortless low-end torque, tractability and lower entry price offered by the 428 and 429 Cobra Jets. Still as engines go, the Boss 429 carved out its own place in history and in NASCAR at least, proved a formidable weapon, giving Ford’s sleek Torinos the edge on the big super speedways between 1969 and 1971.
7. Ford 351 Cleveland This was the last of Ford’s truly high performance engines, first appearing in late 1969 for selected 1970 model year vehicles. Of roughly the same displacement as Ford’s 351 Windsor, the Cleveland was an entirely different engine, being part of the 335 mid-block family that would grow to encompass the 351 M and 400 units. Named after the plant that built it, Ford spent some $700 million to tool the Cleveland and it featured many features also employed on the 385 series engines, including a strong block employing thin wall casting technology, a very strong five-bearing crankshaft, stout main bearings and splayed end caps. It was also distinguished from the 351 Windsor engine by its integrated timing cover at the front of the block. From the outset the Cleveland was conceived as a high performance engine and the four-barrel version featured huge heads with wedge shaped combustion chambers and canted valves, free breathing four-barrel intake manifold and was designed to accommodate large carburetors like the Autolite 700 and 750 cfm units. The two-barrel Cleveland, primarily intended for use in trucks, used different heads with smaller valves and an intake manifold with narrower ports. Unlike the Boss 302, which used versions of the same heads, the Cleveland primarily came with hydraulic valve lifters and a fairly mild camshaft, though an R code version did get a solid lifter bumpstick. It was actually very tractable for such a high performance unit and in four-barrel form, with 300 hp and close to 400 lb-ft of torque, was a good runner on the street.
A couple of interesting variations were the one year only R-code Boss 351, which featured a four-bolt main block on all five crank bearings, stronger pushrods, and an ultra aggressive, high lift cam and solid (mechanical valve lifters), yielding 330 hp and 370 lb-ft of torque. It was an amazing engine and made the 1971 Boss the quickest of the breed in factory trim, but proved very short-lived. The R code engine was available for 1972, but sported new open chamber heads and lower compression, rated at 275 hp (SAE net).
The other Cleveland special, was the Q-code 351 Cobra Jet, rated at 266 hp and offered in 1972-1973 Mustangs. It incorporated many features of the Boss engine, including the four bolt main caps (though not on all five crank bearings) and performance intake manifold with 750 cfm four-barrel carburetor. The Q-code however, featured different open chamber heads and lower compression pistons as it was designed to run on lower grade fuel.
The original Cleveland engine lasted through 1974 in North America, after which the basic block and heads were incorporated into a new engine, the 351 M (Modified) that used the smaller Windsor’s crankshaft, rods and pistons. The taller stroke required a modified block with increased deck height (hence the name). It was mainly used in trucks and in mid and full-size Ford passenger cars through the end of the ’70s, mostly in low performance two-barrel applications.
Not particularly well known, is the 302 Cleveland, an Australian special that was created by destroking the 351 to create a 5.0-liter engine. It featured locally designed cylinder heads that were based on those found on the 351 C two-barrel engine, but with smaller combustion chambers and modified ports and valves for improved flow. This made these engines great performers, even when running on low-grade fuel. The 302 Cleveland was available in Australian Ford Falcons up until late 1982.
8. Ford 2.3 Liter Turbo Most intriguing of Ford’s late-’70s engine offerings in North America, the 2.3 was actually a development of the 2.0 liter Pinto unit and the first American Ford engine built entirely to metric specifications. It featured very European touches such as a belt driven overhead camshaft and short four-cylinder stroke. For the 1979 Mustang, Ford decided to add a turbocharger, which required strengthening the bottom end, specifying new pistons to cope with added boost from the turbo (set at a maximum 6 psi) and a wastegate or blow off valve, used to funnel out excess air away from the turbo once maximum boost was reached. The turbo engine initially came with a Motorcraft two-barrel carburetor and used spent exhaust gases, which were funneled back into the crankcase to reduce emissions. However the combination of forced induction and less than accurate fuel metering, meant that the engine fell foul of California smog requirements and wasn’t certified for sale in the Golden State. In addition, it soon gained a reputation for poor reliability. The electronic feedback carb didn’t always provide an adequate fuel supply to cope with air delivery, especially when the engine was in boost and fractured rods and fried pistons were commonplace, as was spluttering under acceleration, especially when cold. In addition, the turbo caused premature wear on ignition components due to its location which resulted in tremendous heat build up in the engine bay. It was withdrawn from the US market in early 1981 and from Canada in 1982.
For 1983, Ford decided to give it one more try and fitted new pistons and cylinder head with special lightweight valves, plus a single fuel rail and sequential fuel injection, (whereby a fuel jet is employed for each individual cylinder). Ford’s latest Electronic Engine Control IV computer processor was employed to keep track of air metering and precisely deliver the required amount of fuel as well as controlling wastegate operation. With modified exhaust plumbing and a relocated turbo, the result was a much more reliable engine and although power was up slightly (145 versus 131), the biggest difference centered on cold and hot starting, throttle response and fuel efficiency. The following year, engineers fitted an air-to-air intercooler, designed to draw air from above and into the turbo, which increased power to 175 hp and allowed the engine to run higher boost (up to 14 lbs) without running the risk of detonation. Playing around with the electronics and an improved exhaust system with dual outlets, plus bigger fuel injectors, a new camshaft, and a revised turbo with more boost potential, increased power to 205 hp for 1985. Today, the 2.3 liter turbos, especially the EFI versions, are appreciated by a hardy band of enthusiasts who have proven these reliable, tweakable, units can be tuned to kick the stuffing out of many a V8.
9. Ford 5.0-liter V8 Based on the evergreen 302, we’ve decided to devote a special entry to the 5-liter engine as it received enough new parts to consider it a different breed. The story begins with the introduction of the 1982 Mustang GT. Ford decided to fit this car with a modified 302 that featured a redesigned block, special double roller timing chain and a marine specification camshaft. The engine received an aluminum intake manifold and Holley 600 cfm carburetor the following year. For 1985, the block was redesigned with a taller deck height to accommodate a new performance oriented hydraulic roller camshaft and lifters and got a pair of steel tubular exhaust manifolds. For 1986, engineers introduced a new cylinder block with thicker webbing and cylinder walls and greater nickel content. In addition, new flat top pistons were specified, which boosted compression from 8.4:1 to 9.2:1. New cylinder heads with high swirl combustion chambers and shrouded valves were also fitted to improve emissions and combined with a two-piece manifold with long intake runners and 19 lb/hr fuel injectors, helped make the engine a stout stump puller – its 285 lb-ft of torque was all in by 3,000 rpm. Operation was governed by a version of Ford’s EEC-IV processor that used speed density metering to monitor airflow and then add the required amount of fuel. However, despite plenty of low-end torque, the heads and small throttle body and intake runners restricted top end breathing.
The following year, a set of 1985 truck head castings were adopted with bigger valves and both intake runners and throttle body were enlarged (the latter from 58 to 60 mm). This created one of the most formidable, low cost performance engines of the ’80s and one that responded exceptionally well to performance upgrades. A revised metering system with Mass Air flow, which precisely measured the ambient air temperature coming into the engine was added to California bound Mustangs for 1988 and the rest the following year. A new camshaft for 1989 and then changes to the engine calibrations, new hypereutectic pistons for 1993 and then a redesigned intake manifold for 1994, caused power to gradually fall off from a high of 225 hp in 1987-1988, to 205-215 in its final years, but throughout its production run, the 5-liter remained a high watermark and is still one of the most popular engines ever built.
10. Ford 4.6-liter/5.4 liter Modular V8 First introduced in 1991, the 4.6-liter Modular V8, so named because it was the first of a family of engines that could be built on the same assembly line, was a modern, single overhead cam design, featuring aluminum heads on a cast iron block. It was introduced for use in Mustangs beginning in the 1996 model year and featured a unique polymer cast composite intake manifold and updated ignition system. It was rated at the same 215 hp and 285 lb-ft as the old 5.0-liter it replaced, but it’s smaller displacement and overhead cam design meant that it performed best at the middle and higher end of rpm spectrum, which was different from what most Mustang drivers were used to.
Engine control functions were performed by Ford’s EEC-V processor, that succeeded the old IV and was much more powerful, featuring self testing and On Board Diagnostics that allowed it to monitor operation of the engine’s emissions control system and alert any defects. Minor tweaks to the electronics increased power to 225 hp for 1998 and then the following year new Power Improved cylinder heads with bigger valves and modified combustion chambers; plus camshafts with more lift and greater duration and a new intake manifold design, promoted better flow through. New bottom end bearings reduced friction and actually helped power increase to 260 hp and torque to 302 lb-ft.
In 2003, Ford of Australia introduced a new three-valve cylinder head and for 2005, a version of this found its way onto the Mustang engine with variable camshaft timing and a Charge Motion Control Valve system, designed to reduce emissions and improve throttle response right across the rev range. With 300 hp and 320 lb-ft of torque on tap, it was smooth, reliable and torquey, making the new Mustang GT one of the best bang-for-the-buck performance cars on the market.
Besides the SOHC unit, Ford also released a Dual Overhead Cam version for the 1996 model year in Mustangs (variations of this engine had first been seen in 1993). This differed from its cousin in featuring an aluminum block with six-bearing main caps and massive alloy heads with dual cams and split intake ports for each cylinder, along with variable length intake runners that were vacuum activated. Like the single overhead cammer, it featured a much more modern ignition system than the old 5.0 and was controlled by Ford’s EEC-V processor. Rated at 305 hp and 300 lb-ft of torque, it was smooth and sophisticated and liked to rev way beyond 5,500 rpm, much like the old Boss 302. For 1999, it received new cylinder heads, camshafts and a revised intake design with fixed instead of variable length runners and a new coil-on plug ignition system. This resulted in a broader spread of power than the previous version as well as an increase – 316 hp and 320 lb-ft of torque. However, disappointment from both Ford’s own engineers and customers, caused production to be suspended and tweaks made to the electronics, boosting power to a 320 hp (the original target figure) by 2001. All of these engines were hand built by a special two-man team at Ford’s engine plant in Romeo, Michigan, just north of Detroit.
A variation of this engine was installed in the 2003-2004 Mach 1 Mustang, with different intake camshafts, borrowed from the Lincoln Navigator’s 5.4 liter V8 (to promote greater torque) and featured a unique block casting and higher compression ratio (10.0:1, versus 9.85:1 on the Cobra engine). Cars equipped with five-speed manual gearboxes got a forged steel crankshaft, while those with automatics got a cast crank. Power was 305 hp and 320 lb-ft of torque in 2003 and 310 hp and 325 lb-ft in 2004.
The 2003-2004 Cobra engine, was based on the 4.6 all-aluminum unit, but got a much stronger, cast iron block, Manley H-beam forged connecting rods with modified wrist pins to improve oiling and, special forged pistons. Bolted to the top of it was a unique intake manifold and Eaton/Roots M112 centrifugal supercharger, tuned to deliver a maximum of 8 psi of boost. This engine was factory rated at 390 hp and 390 lb-ft of torque, but on the dynometer, 2003 Cobras were easily putting this amount of power to the tires. The block and bottom end of these engines are incredibly stout and have proved capable of withstanding over 800 hp with factory parts.
Bigger brother to the 4.6 liter is the 5.4 Modular V8 and for the purpose of this article we will focus on the DOHC versions that came in the 2000 Mustang Cobra R and the 2007-2009 Shelby GT 500. Both these engines feature cast iron blocks – the Cobra R unit got a forged steel crankshaft and special billet steel Carillo connecting rods, plus 9.6:1 compression forged alloy pistons. Special high flow cylinder heads featured unique performance camshafts, with greater lift and more duration than other 5.4s to maximize breathing. The Cobra R engine also featured a special high rise cross ram intake manifold to increase airflow and tubular exhaust headers linked to Borla stainless pipes. Power was listed at a mighty 385 hp and 385 lb-ft of torque, though even some thought that was conservative.
The Shelby GT500 engine utilized a cast-iron block shared with the Lincoln 5.4, but unlike the Ford GT super car, used a wet sump oiling system from the Mustang GT. However, the Shelby engine did use Ford GT super car heads, but they were modified to utilize 2003-2004 Mustang Cobra camshafts and unique valvetrain and cam drive components, in order to fit in the Mustang’s engine bay. Like the old 2003-2004 Cobra, the GT500 engine featured a positive displacement supercharger, in this case an Eaton M122 unit, set for a maximum of 8.5 psi of boost, plus an air-to-oil intercooler to feed the cold air charge and a unique dual-bore throttle body borrowed from Ford’s 6.8-liter truck V-10. In factory trim the GT500 engine is rated at 500 hp and 500 lb-ft of torque, though it is easily capable of far more. For 2008 it was tuned to deliver 540 hp in the limited production GT500 KR, making it the most powerful engine ever installed in a factory built Mustang. Will we see anything to topple that? At the present time, that remains to be seen, though with the likes of 500 plus hp Corvettes already running round, anything is possible.