Tom Wilson
May 6, 2011

When the cherry picker meets the metal, the point of most engine swaps is to get the most powerful engine into the smallest car. It’s the way cars should be built in the first place, we figure, but sometimes the factory needs a helping hand and you end up doing the job yourself. Let’s face it--it ultimately would be easier to buy a car with the engine you want already there, but a car with a swapped engine is always going to garner more attention and carry more street cred that an off-the-lot install.

Now, if there ever was a poster boy for the phrase the devil is in the details, the engine swap is it. In the zeal for more power, it’s easy to over look some of the physical realities of a monster engine or the numerous logistical headaches they pose. To put it bluntly, compared to the modern steady diet of bolt-ons, an engine swap can generate headaches because there are plenty of decisions to make and often parts to build. To help, we’re presenting this overview of common Ford engine swaps. We want you to gain a feel for what the finished swap is like and it’s relative difficulty.

Let’s observe that besides being great fun, engine swaps are generally a hassle. The car is typically an immoveable lump in the garage for weeks, and you spend the majority of the time chasing little stuff such as brackets and wiring diagrams. Get adventurous with a truly exotic swap, and you could find yourself getting schooled in why exhaust headers cost so much when you have to design and build your own, or learning far more about electronics than you dreamed possible thanks to a modern computer that wants to know what the brake lights and electric power steering are doing before it will turn on the engine.

Because of this hassle factor, we strongly suggest--demand would be a better word--that firsttime swappers or those without a reasonably complete home shop and fabrication skills stick with common engine swaps that are well supported by aftermarket parts. And for the same reasons, engine swaps are best reserved for hobby cars, not daily transportation.

A major consideration is electronics because the cars in question span the carburetion-to-electronic fuel injection divide, and EFI has been evolving ever since. There are endless variations in wiring harnesses and their connectors in the last 25 years of Mustang production to accommodate model years, variations in automatic versus manual transmissions, and 49-state versus California or 50-state cars, among other things. There are also return and returnless fuel systems, distributor, distributorless and coil-on-plug ignitions, plus mechanical and electronic throttle bodies, anti-theft keys, electric power steering, variable cam timing, and more. In general, the pros tell us the ’05 Mustang ushered in a new level of electronic complexity and the ’11 Mustang seems to have made an equally large jump.

Luckily the aftermarket has been working hard on adapting these various systems. We don’t have space to list them all here, but the most important are the recently introduced Control Packs from Ford Racing. These are a godsend to Three-Valve 4.6 and Four-Valve 5.4 swaps, as well as their intended purpose of supporting FRPP crate engines in kit car and street-rod swaps. And don’t overlook carburetion for simple track or strip cars. It can save you many headaches, and you can always return to EFI later if desired.

Much of what we call engine swaps today are actually crate-engine installs. Traditionally an engine swap is best supported by buying as much of the donor car as possible to gain cost-effective access to supporting pieces such are wiring looms, brackets and such. That’s not possible with a crate engine install, so think through where all the parts are coming from before writing any big checks. Remember, the big parts are easy, it’s the little stuff that’ll devil you.

All that said, an engine swap can be the easy, inexpensive, and durable path to big-displacement fun, or it could also be the right choice for modernizing an older chassis with newfound smoothness and speed. And don’t forget, you can always supercharge a big engine too!

Horse Sense: The June ’02 issue of 5.0 Mustang & Super Fords has several engine swap articles detailing some of the swaps we discuss in this story. For converting a 3.8 SN-95 to 5.0 power, see the Feb. ’09 issue. If you can’t find the printed magazines, the stories are available online at www.50mustangandsuperfords.com.

From the June 2002 issue
Eight from Four: Fox Mustang 2.3L to 5.0L Swap Guide
Should Have Had a V-8: 1994 - 98 Mustang V-6 to V-8 Conversion
Displacement Replacement: Swapping Your Mustang's 5.0L for a 351W

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Pushrod 5.0

This is one of the easiest swaps because readily available, stock factory parts are all you need to replicate a 5.0 LX or GT from a humble 2.3. Furthermore, if you’re interested in what the swap will turn out like, just drive a 5.0 Fox. In fact, because there are so many V-8 Foxes still available, our first advice is to consider selling your 2.3-liter project Fox and buy an H.O. as your starting point. It’s often the quicker, less expensive, and easier option.

On the other hand, converting a four-banger can be a smart move. By now old Fox Mustangs need everything, so ditching a pile of wasted, puny four-cylinder driveline parts is a no-brainer if you’re installing a 31-spline rear axle, T-56 trans, a new suspension, and big disc brakes anyway. That makes this swap especially appealing for race cars and Saturday night shakers--cars that care little about interior niceties and depend more on an unwrecked, rust-free unibody than anything else.

Conversely, if you’re going for a clean street car, you’re almost always better off starting with the cleanest street 5.0 H.O. you can afford and selling that four-banger your uncle gave you. This is especially true if considering an early Fox with a brittle SROD transmission or 7.5-inch rear axle.

Technically, the V-8 into a four-cylinder Fox swap can be accomplished with little more than a V-8 engine, engine wiring harness and computer, but as the horsepower goes up, so does the need for more robust supporting pieces, such as larger radiators, better clutches, bigger fuel pumps, and so on, so don’t overlook those upgrades in your planning.

Two-Valve 4.6

Like putting a pushrod 5.0 in a four- cylinder Fox, slipping a Two-Valve 4.6 into an SN-95 is simply duplicating what the factory has already built in the Mustang GT. Once again we say you should take a hard look at simply buying a V-8 Mustang as the starting point and selling whatever V-6 car you may already have. That’s not always the best move depending on what you’re aiming for in the finished project, but it’s definitely something to consider.

An advantage to the SN-95 is there are fewer differences between the V-6 and V-8 versions. This is especially true with the ’99 and later New Edge cars, which all came with a 3.27-geared 8.8-inch rear axle. The ’99 and later GTs all sport coil-on-plug ignition, too. That’s one less wiring hassle when wiring in a later modular V-8.

One significant difference is the ’94 and ’95 GTs, which used 5.0 pushrod engines and classic EEC-IV engine management, while the same year V-6 cars had already moved on to OBD-II electronics with a data port. When the 4.6 Two-Valve went into the GTs in ’96, they too were OBD-II cars. Another detail is all manual-transmission SN-95 GTs use a T-45 gearbox as opposed to the T-5 in the previous Fox cars. The meaningful difference is the T-45 has an input shaft that’s 5/8-inch longer than T-5. It was needed because Ford actually moved the engine slightly forward in the SN-95s.

Pushrod 5.8

When Ford developed the 351 Windsor, it invented the best reason to swap engines--displacement in a compact, affordable package. We’re not going to get too deep into the 351 swap from a nuts and bolt standpoint because it’s a well-known job and reasonably straight forward. That, and there seems to be as many ways of making a 351 work as there are 351 swaps because the aftermarket is positively dripping with parts.

That said, the only Mustang since the ’70s to get the 351 was the rare Cobra R (only 250 were built). That gave us all the parts when dropping one into an SN-95, but you’ll need more help in a Fox or New Edge. Start by reading 351 Engine Swap from our May ’01 issue. It’s online and gives the necessary details (www.mustang50magazine.com/techarticles/18818_351w_engine_swap/index.html).We also highly recommend Maximum Motorsports (www.maximummotorsports.com) K-member for this swap to offset the heavier engine’s weight and open up header room. The gain in handling is important, too.

What we’d like to concentrate on is why the big Windsor is such a good swap. Most importantly, exceeded only by the behemoth 460, the 351 offers far more cubic inches of displacement than the pencil-neck modulars or the tightly packaged 302. Even better, the 351 can be built to well over 400 cubes with passable durability, and those engines pack an immediate low- and midrange torque hit that’s a blast to drive.

Windsors are durable, too. Even the stock blocks are notably stouter than 302 blocks, and the heavy-duty FRPP Sportsman and aftermarket blocks are anvil tough. But they aren’t big! A 351 poked and stroked to 427 inches is much more compact than a 281ci modular; this makes them far easier to install and work on. These engines aren’t overly expensive in near-stock trim, either, although a full-house stroker will add up for sure.

The downside to the 351 is that it’s a full notch heavier than the 302, and the legacy Two-Valve pushrod design does not match the newer modular in smoothness, fuel economy, or breathing without good aftermarket cylinder heads. But for quickie street-oriented performance, the easy low-end torque is sure to please; if major power is wanted, there are race heads and big displacement on your side.

Three-Valve 4.6

We’ve been surprised we don’t see more Three-Valves in pre-S197 Mustangs. The Three-Valve is an excellent performer and readily available; it would seem the cost-effective modular swap for pre-’05 Mustangs. It’s definitely lighter and easier to work around than the bulky Four-Valve engines, not to mention far less expensive. Slipped into a lighter chassis (anything is lighter than the S197), the Three-Valve promises never-get-tired-of-it thrust.

Paul’s High Performance (www.paulshp.com) has performed every engine swap mentioned in this article more than once, and main man Paul Svinicki says the Three-Valve performs nearly as well as a Four-Valve. Unless you just have to have a Four-Valve, Paul assures us that the Three-Valve is easily the better choice for most people.

What seems to have happened is the suave new S197 Mustang is so nice that, once again, it’s made more sense to simply buy an ’05-’10 Mustang instead of swapping its engine into an earlier car. That, and what engine swaps that have taken place were the Four-Valve 4.6 Cobra engines--Terminators or more likely Mach 1, Marauder, and early naturally aspirated Cobra engines just because they’re sexier.

Not incidentally, we’re also getting into a more complex swap because the Three-Valve has an electronic throttle and provides no idle circuit along with variable cam timing, and thus a different wiring harness and computer, plus the exhaust ports differ from the Two-Valve’s. This complicates the swap when back-dating into the less sophisticated SN-95s and seemingly pre-historic Foxes. For years Logan Motorsports has had the answer with a kit that addressed these concerns, but at the price of locking-out the variable cam timing and a cable throttle body. Now Ford Racing has its Control Pack for the Three-Valve. It keeps the desirable variable cam timing (better torque, fuel economy), but at a cost of $1,350. You may also still want Logan’s exhaust adapters to mate the Three-Valve ports with Two-Valve manifolds or headers that fit the S197, which might require moving a bung or EGR tube.

Mechanically the Three-Valve’s modular bellhousing and engine mounts are totally different than the Foxes’ pushrod pieces, so you are really redesigning the powertrain in that swap. Putting the Three-Valve into the SN-95 is less difficult because it’s at least a modular-to-modular swap, so transmission fitment requires no adapters. Ultimately this is a compelling, cost-effective swap that seemed destined to be overshadowed by either the Four-Valve Cobra or later Coyote 5.0 swap, but it should gain ground now that FRPP is offering a complete support kit in the Control Pack.

Four-Valve 4.6

Once again we’re talking about re-creating a car that Ford already built in the ’96-’01 Cobras and Mach 1s. So if a Mach 1, early Cobra, or Marauder engine came your way, you could swap it without much difficulty. The result is a nice bump in power, with a smooth-driving 315 hp or so from a Mach 1 Four-Valve. Technically the naturally aspirated Four-Valve engines swap without much trouble into the ’96-’04 GTs. Most of the connectors are the same for the injectors, oxygen sensors, mass air, timing pickups, and more, so wiring hassles are few. The six-bolt bellhousing pattern of a Mach 1 or Marauder is also a bolt-in. More good news is the exhaust, oil pan, throttle cable, and GT computer will work with the Four-Valve. This is a good swap when planning on pumping up the Four-Valve with a blower, nitrous, and so on.

Terminator 4.6

At some point an engine swap goes from an interesting challenge to impossible for the home mechanic, and that line lies between the naturally aspirated Three-Valve 4.6 and Terminator Four-Valve swaps. There are two reasons the exciting supercharged ’03-’04 Cobra engines are beyond the capabilities of a home garage enthusiast--the engine’s physical size and the complexity of its electronic controls. Together these make swapping the Terminator into an earlier Mustang daunting. While it can be done, but it is often too expensive and too encompassing for the average guy.

But as noted, it can be done. On the physical size standpoint, you’ll need Hydraboost (or manual brakes) to clear the valve covers, you’ll want the Terminator’s gas tank and fuels pumps, and you’ll find plenty of fabrication work hanging the charge cooler radiator, relocating the radiator, making a rear transmission mount, an so on. Electronically the Terminator wiring runs to the instruments, the transmission, and as far away as the taillights, with GEM and fuel pump modules previous cars don’t have.

In short, installing a Terminator in an earlier Mustang is pretty much installing an ’03 Cobra’s brains and mechanicals into the bodyshell of another car that wasn’t particularly designed to accept it. It is definitely a pro job.

All of this adds up. A Terminator engine is about $8,000; the transmission, $4,000; and it takes 60 to 100 hours of pro labor to put it all together. That’s another $8,000 or so, and that doesn’t begin to include the upgraded suspension, brakes, blowers, fuel systems, sound systems, and other stuff such massive projects tend to attract.

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Coyote 5.0

Ford Racing is pushing the Coyote as a crate and swap engine, and with its introduction of the M-6017-A504V Control Pack for the Coyote/manual trans combination, the swap future of this exciting new engine is guaranteed. With minimal tuning, it offers well over 400 super-smooth horsepower, great fuel mileage, light weight, and new-engine coolness.

At the moment there isn’t much knowledge of the Coyote as a swap motor because it’s so new. We’ve seen a Fox installation that seems to have gone well, and with the aftermarket tooling up headers and other supporting pieces, we believe the Coyote will offer the most sophisticated, newest design engine in a real-world install package for all S197 and earlier Mustangs. It won’t be as inexpensive as pushrod power, but it will require far less coin than a Terminator 4.6 or GT500 5.4, and offer no-excuses power potential.

Technical hard points center around the Coyote’s involved electronics and electric power steering. FRPP’s $1,500 Control Pack answers the electronic issues, and KRC Power Steering is working on an add-on hydraulic power steering pump. BBK already has a long-tube swap header for Foxes with a matching X-pipe, extra wideband O2 sensor bungs, and you choice of cats or off-road configuration, plus High Flow Fuel Systems has return and returnless fuel systems to suit.

Early interest in putting a 5.0 in a 5.0 has given us our first Coyote/Fox hybrid. The news is that the Four-Valve Coyote 5.0 fits without cutting anything, and because the ’96-’04 4.6 engine mounts are a bolt-on, Maximum Motorsports 4.6 Fox swap K-member is the way to go. Bellhousing bolt pattern matches the 4.6/5.4, so the usual transmissions are a bolt-up proposition, and overall engine length is essentially the same as a 4.6, so we don’t foresee issues in the SN-95 or New Edge engine compartments.

GT500 5.4

Some folks we talked to described this as a nightmare swap when discussing shoehorning the tall and wide 5.4 into a pre-S197 Mustang. It’s inches taller and wider than anything else, including a 460. Engine size isn’t the only issue, as the weight of the earlier iron-blocks is a concern, both its mass and high placement. Of course, if you’re moving it into an early car, a GT500 requires endless fabrication to accommodate its numerous accessory systems, such intercooler pumps, and charge cooling water radiators, as well as fitting Hydraboost braking (or going manual), plus adding the necessary strengthening in a Fox, SN-95, or New Edge. Naturally, FRPP has a Control Pack, which greatly simplifies the wiring of the engine controls in an earlier car.

Of course, that’s if you are going back to a Fox like our Fox 500 project. Moving a GT500 5.4 into an S197 is a far less daunting task. With a proper donor car, you can swap the engine, trans, and wiring straight over with only a few wiring quirks. In fact, one of our feature cars in this month’s issue, owned by Alex Pappas, was converted from a Three-Valve to a GT500 5.4 in an incredible five days by an experienced swapper. 5.0

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Honorable Mentions

460 Big-Block
Back in the mid- to late-’80s, plopping the giant 460 anvil into then-new Fox Mustangs had its 15 minutes of fame. These were sinfully heavy all-iron big-blocks that produced mountains of chassis-twisting torque in near stock form and untold power fully hot-rodded. In short, they proved too much for a Mustang, and today the same torque and power can be had in a 200-pound-lighter package. But if you insist, the headers and carburetors are still available, and you can get 514 ci from one of these without trying too hard or 600-plus inches on a big budget.

EcoBoost V-6
Ford engineers must have an F-150 EcoBoost V-6 powered Mustang somewhere in Dearborn, but we’ve yet to see one. It would make a great conversation piece and a sharp-handling Mustang with approximately ’11 Coyote straight-line performance (or better in a lightweight Fox?), but without factory support it would be impossible to wire up. Only the most experienced and well-connected pros should try this one.

3.7 V-6
We doubt anyone would bother with this swap unless they prized handling above all else, even if the straight-line performance should easily out-run a ’96-’98 GT. Still, the resulting car would be a novelty--although given the still-as-yet-unknown complexities of the newest V-6’s engine management, a nearly impossible stunt to pull off.

6.2 V-8
Sold as the base engine in Super Duty pickups and the SVT Raptor F-150, the new 6.2-liter V-8 is the stuff of exotic Mustang swaps. There are no kits and the large 6.2 measures 3.5-inches longer and a 1/4-inch wider than a Three-Valve V-8; it packs unique engine mount placement and who knows what electronic gremlins. But the bellhousing pattern is stock modular, not to mention it’s a beefy 380 ci and the cylinder heads support 750 hp with minimal hand detailing. There’s a reward of fame here for the pioneering Ford enthusiast, but it would be hard-earned.

Glossary

We’re as guilty as anyone for using Ford jargon. Here’s a quick explanation in case you’re new to the club.

Engines
5.0 HO’82-’95 302 pushrod V-8, the original 5.0
Two-Valve’96-’04 Two-Valve modular 4.6-liter V-8
Three-Valve’05-’10 Three-Valve modular 4.6-liter V-8
Four-ValveAny Four-Valve modular 4.6-liter V-8
Coyote’11 Mustang GT engine, the new Four-Valve 5.0
Early Cobra’96-’98 4.6-liter Mustang Cobra Four-Valve, naturally aspirated
Late Cobra’99 and ’01 4.6-liter Cobra Four-Valve, naturally aspirated
Terminator’03-’04 4.6-liter Mustang Cobra Four-Valve, supercharged
GT500’05-’11 5.4-liter Mustang Cobra Four-Valve, supercharged

Chassis
Fox’79-’93 Mustang, lightweight, excellent parts support
SN-95’94-’98 Mustang, inexpensive, still sort of lightweight
New Edge’99-’04 Mustang, a restyled SN-95
S197’05-’10 Mustang; modern, tight chassis; heavy