Ford Modular V-8 Engines Explained

As vintage Ford enthusiasts, many of us have been slow to embrace Ford's newest engine technology--the 4.6 and 5.4 SOHC and DOHC Modular V-8 engines. We like the familiarity of the small-block Ford, the FE big-blocks, the Cleveland, the 385-series fat-blocks, and even the old Y-block V-8s. We grew up on rocker arms, pushrods, and real iron, and as a result, we've never published much on the Modular V-8 engine family.

But we're into more progressive thinking these days at Mustang & Fords, which is now under the guidance and direction of Editor Mark Houlahan (whose most recent gig was senior technical editor at 5.0 Mustang & Super Fords), so it's time to learn as much as we can about Ford's newest generation of overhead cam V-8 engines. We visited Power Heads/Modular Racing in California for a look at Ford's venerable Modular V-8. We also gave a shout to the Modular fanatics at Ford Racing, Sullivan Performance, and True Blue Performance to answer some of our questions.

The Modular V-8 engine isn't new. It was introduced in the '91 Lincoln Town Car 15 years ago. Then it appeared a year later in the redesigned '92 Ford Crown Victoria and Mercury Grand Marquis. In 1994, it was introduced in the Thunderbird and Cougar; in 1996, it debuted in the Mustang GT and SVT Cobra. Early in 1996, the Modular V-8 found its way into the redesigned '97 F-series truck line; after that, the E-series vans, as both a V-8 and a V-10; then, the all-new Super Duty F-250/350, as a V-8 and a V-10.

The Modular V-8 is as deeply entrenched into the Ford psyche' today as our pushrod V-8s were during the '60s and '70s. It is very much at home with Ford performance enthusiasts, and likely here to stay for a long time to come. For 2005, Ford has introduced its newest version of the Mod motor with a three-valve cylinder head and cast-aluminum cam covers. The three-valve head can be found in the all-new '05 Mustang GT on top of the 4.6 short-block, and the '04-'05 5.4 F-150 and Expedition. This head has made a huge difference in low-end torque, making the 4.6 and 5.4 V-8s snappier down low where it counts--at the traffic light.

The Modular V-8 didn't get its name from its design. The name was derived from its manufacturing plant protocol--Modular--because the engine plant can be changed out in a matter of hours to produce different versions of this engine family. That said, the Modular V-8 and V-10 engine family is certainly different from our proven pushrod V-8 engines of yore. for one thing, it is huge, impossible to fit into a classic Mustang or Fairlane without significantly modifying the front end. However, it's a nice fit for the big Fords--the Galaxies and Customs. It's also a comfortable fit for the classic F-series pickups. Sit a 4.6 Mod motor next to a Boss 429, and you will find the 4.6 and 5.4 engines are larger in every respect. They're large, yet small, with displacements of 281 ci and 345 ci, respectively. What makes these engines so large is their wide overhead cam cylinder heads. In this first half of our look into the Modular engine family, we'll get you acquainted with the Modular short-block and its internal nuances. Next month, we'll wrap things up with a look at cylinder heads and induction for the Modular family.

SOHC Engines
When Ford introduced the 4.6 SOHC V-8 in 1991, it was vastly different than any Ford V-8 we had ever seen; it hardly seemed a Ford powerplant. Yet, like the old FE-series 427, it had block main skirts and cross-bolted main caps for rigidity. And like the 427 SOHC, it had a single overhead cam design and a whole lot of chain, which made it larger. Outside of those two features, the 4.6 SOHC V-8 really was a different engine altogether.

The 4.6 SOHC sports a rigid iron block capable of handling high-rpm operation and channeling a lot of power across its lean looking crankshaft with knife-blade counterweights. From front to rear, the Modular V-8 is shorter than the small-blocks and big-blocks it replaces. From side to side, it's much wider. In full dress, it tends to be heavier, around 600 pounds. It has nothing in common with any of the pushrod V-8s already mentioned. What's more, the Modular V-8 doesn't enjoy the same kind of interchangeability as its predecessors. The Modular engines tend to be different from one plant to another, from one model year to the next, and from one carline to the other. It takes a solid understanding of this engine and its many castings to build it and make power.

When Modular V-8 production began 15 years ago, there was one engine plant: Romeo, Michigan, the old Ford tractor plant outside of Detroit. in 1997, Ford added a second Modular V-8 plant at Windsor, Ontario, to produce 4.6 and 5.4 SOHC engines for primarily trucks. Eventually, the Windsor plant would produce Mod motors for an even greater number of car lines. If may surprise you to know the Windsor engines are considerably different than their Romeo counterparts. Very little interchanges from one plant to the other.

DOHC Engines
In 1993, Ford introduced the 4.6 DOHC engine in the Lincoln Mark VIII. What made the 32-valve Modular V-8 different was its all-aluminum construction. This engine witnessed exclusive use in Lincolns until 1996 when it was then introduced in the SVT Mustang Cobra. The DOHC approach was carried over to the Lincoln Navigator in the late '90s with the 5.4 DOHC V-8 with an iron block and aluminum heads. These DOHC engines make excellent powerhouses for vintage Fords, thanks to their lightweight, cross-bolted main cap design.

This engine is terrific looking for a vintage Ford engine compartment because it is massive, with extra-wide cylinder heads and cam covers. It is right at home in a full-size Galaxie or Marauder, and worthy of engine compartment indigestion in a Mustang or Fairlane.

Blocks
If you're building a 4.6 SOHC engine, you need to know there are two basic Windsor block castings, and four basic Romeo block castings. It's a good idea to keep Windsor heads with Windsor blocks, and Romeo heads with Romeo blocks to eliminate any confusion in your engine build. If you're going to interchange parts and castings between the two plants, you better know exactly what you're doing or expect all kinds of disappointment, wasted time, and expense.

Romeo SOHC
The Romeo blocks have casting numbers much like our old pushrod V-8 blocks. Expect to see F1AE for 1991, F2VE for 1992, and F4VE for 1994 (there were no F3VE castings in 1993). These early iron blocks were all cross-bolted across four of the five main caps. It can safely be said the F2VE block is identical to the F1AE block. These early Romeo blocks had two-bolt starter provisions. The rest have three-bolt starters. Early F1AE and F2VE blocks had the same bellhousing bolt patterns as the small-block Fords.

A redesigned Romeo block was introduced in 1996 as F65E-CC, F6VE, and F7VE, with five cross-bolted main caps and a knock sensor provision in the valley. Despite the three numbers, these castings are all the same. The "V" in these casting numbers indicates Lincoln. Romeo truck blocks got the "5" that went into the '97 F-150 trucks. What makes the truck block different than the Lincoln block is the oil cooler provision on the left-hand side--one extra bolt hole midblock. There was also an F6AZ-CB Romeo block specifically for the '96-and-up Mustang GT.

The F7AE block was conceived primarily for the '97 F-150 and F-250 pickup trucks. Expect to see it in a lot of other Fords and Mercs of the era, including the Lincoln. There was also a F7VE block, which was more Lincoln specific. Expect to see it in a variety of Ford applications. In 1999, Ford began producing the XW7E block, which allowed for relocation of the oil filter to the rear of the engine away from the cross member.

Another important issue to remember is the cross-bolted main caps. Early 4.6 engines had torque-to-yield cross-bolts--also known as jackscrews--that pulled the main caps tight to the block's side skirts. About 1996, the jackscrew-style cross-bolts were dropped in favor of precision spacers/dowels and conventional bolts.

Windsor SOHC
The Windsor foundry and engine plant first began producing Modular V-8 engines in 1996. In your search for a block, you're likely going to see similar casting numbers between Romeo and Windsor, but similar numbers do not mean similar castings. Those first Windsor block castings are numbered F65E-BB and F75E for the '97-'98 F-150 and F-250 trucks. That is the significance of the "5" in the number. The F65E-CC Romeo block, though a truck block, will not interchange with the F65E-BB Windsor block. All five main caps in the F65E-BB and F75E blocks are cross-bolted. What makes the Windsor block different than the Romeo block are the dowels between the main caps and the block instead of the jackscrews used at Romeo. Windsor blocks typically have a "W" logo on them somewhere, location varies.

The 5.4 block (F75Z) is similar to the 4.6 block, except for deck height. It is a taller block, just like the 351W is taller than the 289/302 block. The 5.4 deck is 10.079 inches instead of the 4.6's 8.937 inches. Because the 5.4 SOHC had its share of problems early in the going, Ford revised the block in 2001, using more iron to improve reliability.

With these iron-block SOHC engines, expect a cylinder wall thickness of .110-inch thickness on the thrust sides of the wall and .165 inch on the fore and aft sides. This means you can bore the 4.6 and 5.4 engines .030-inch oversize. We strongly advise against a larger overbore.

DOHC
According to Sean Hyland's book, 4.6-Liter Ford Engines, Teksid of Italy, a supplier to Ferrari, cast those first aluminum blocks. This remains the strongest 4.6 DOHC block available. according to Hyland, these blocks received special treatment. They were cast in SAE 319-modified aluminum alloy, heat treated, and aged for strength.

Beginning in 1999, the Windsor Aluminum Plant (WAP) entered the production picture, producing the 32-valve (DOHC) blocks. Ford beefed up the 4.6 DOHC block, giving it extra ribbing for both strength and quiet operation. The pan rail was also thicker for both strength and reduced noise and vibration. Although the extra ribbing may look impressive, it's there because there is less aluminum in the casting. Keep in mind, this doesn't always make it a better block. The best block to use is the earlier Teksid casting (prior to 1999) if you're going to be doing some serious racing. The Teksid block casting can stand up to 900 hp, according to Hyland. He also says the Windsor aluminum block can take up to 600 hp.

Although we tend to think of the 4.6 DOHC engine as a rear-drive engine, Ford used it in a front-drive application in the Lincoln Continental. The front-drive Continental employed a different block than the rear-drives, with different bosses for the mounts and a different bellhousing bolt pattern. It will not fit in your rear-drive Ford or Merc.

Because the 4.6 DOHC engine is all-aluminum, it is fitted with ductile iron cylinder sleeves. The best thing about this design is being able to swap these sleeves (liners) as the need warrants. Granted, it is not an easy process, and best left to a professional, but it is a great way to salvage a block. Ductile iron and aluminum alloy cylinder sleeves are available from the aftermarket. With these cylinder sleeves, you can up the displacement to over 300 ci. Mix in some stroke from one of the aftermarket stroker kits, and you have real power from your 4.6 DOHC.

Crankshafts
From 1991 to 1995, one basic nodular iron crankshaft was produced for Romeo 4.6 SOHC engines--numbered F1AE. It is a five-main-bearing crank with narrow, knife-edged counterweights. During the same period, there was a steel-forged F2LE-AG crank conceived for the 32-valve DOHC 4.6 Cobra engines. This crank is not designed for the SOHC engine, so don't even go there if you're building a SOHC. Beginning in 1996, a new crank was used in the 4.6 SOHC Romeo engines: the F65E steel crank.

When the Windsor engine plant came on line in 1996, it produced its own array of crankshafts, primarily for trucks. This is also an F65E steel crank designed for the Windsor block. Where this gets confusing is the crankshaft flange. Some were six-bolt and others were eight-bolt. Rule of thumb: most Windsor F65E steel cranks have eight bolt holes, only some have been spotted with six.

Like the 4.6 SOHC engine, the DOHC engine is fitted with a lightweight, knife-blade counterweight crankshaft with wide main journals and smaller rod journals. Architecturally, it is virtually the same as the SOHC. The Lincoln 4.6 DOHC engines were factory-fitted with nodular iron crankshafts that could spin happily to 6,500 rpm. Mustang Cobras got the steel crankshaft for greater durability in a high-performance application. The steel crank is configured differently, with additional counterweights at the No. 3 main journal. The steel crank has eight flywheel bolt holes instead of the six we generally see in the SOHC.

The 5.4 started out in 1996-'97 with a forged steel crankshaft for truck use. This pattern continued until 1999, when Ford went to a nodular iron crank in the 5.4 SOHC. The nodular iron crankshafts in both the 4.6 and 5.4 SOHC engines can take up to 500 hp. If your goal is higher, plan on a steel crank.

Connecting Rods
What makes the 4.6 SOHC rod different than those we find in the older pushrod V-8s is its powdered-metal design with cracked caps. Powdered metal is formed in a mold, then the rod is scored, and the rod end separated (cracked). The cracked cap design makes each connecting rod as unique as a fingerprint. The 4.6 SOHC rod is also longer and leaner than we are used to with older Ford powerplants. Rod bearings are smaller and wider for better load distribution. Romeo rods differ from Windsor rods because they employ pressed-in pins. Windsor rods are all full-floating pins. Powdered-metal connecting rods work quite well in street applications, but they get shaky when we start hammering on them with nitrous or supercharging.

The 4.6 DOHC is fitted with the same powdered-metal connecting rods we find in the SOHC. The one exception to this rule is the '03-'04 SVT Mustang Cobra that has Manley forged steel rods for use in this factory supercharged application. If you're going to really spin your 4.6 or 5.4 engine, powdered-metal rods are a bad idea above 400 hp. if you plan on racing, aftermarket forged steel I-beam and H-beams rods are available for the Modular V-8s.

Pistons
Word in the industry is, there were three basic pistons used in the SOHC engines from 1991 to 1999: one type for the Romeo SOHCs and two in the Windsors. The Romeo piston is a press-fit-type hypereutectic with a dished crown. Because Ford was aiming for reduced friction, the rings aren't what we're used to with the older Ford engines. The rings are much thinner at 1.5 mm (both compression rings) and 3.0 mm (oil ring pack). Because the Windsor rods sport floating pins, they are bushed and call for a different hypereutectic piston than we find in the Romeo SOHC engines. Windsor pistons, like Windsor engines, came along first in 1996 and remained the same until 1999.

Beginning in 1999, Ford fitted the 4.6 SOHC with a better cylinder head called the Power Improved (PI) heads. With those PI heads came a new piston with a deeper dish to allow for a smaller heart-shaped chamber size. Another dynamic common with 4.6 and 5.4 engines is coated piston skirts for reduced friction at the thrust faces. Ford opted for hypereutectic pistons in order to run tighter piston-to-cylinder wall clearances. Running tighter clearances reduces emissions. It also enables these engines to make more power through better cylinder sealing.

The 4.6 and 5.4 DOHC engines run domed forged pistons for increased compression in the four-valve chamber. Ford opted for forged pistons to withstand the pressure extremes associated with this high-performance engine. Like the hypereutectic pistons in the SOHC, these pistons also employ Teflon-coated skirts for reduced friction and heat protection. The ring package is virtually the same.

The '99-'03 Ford Lightning 5.4 SOHC supercharged V-8s were fitted with forged pistons for obvious reasons--supercharging. Higher cylinder pressures make forged pistons mandatory.

The aftermarket offers enthusiasts a wealth of piston types for the Modular V-8s. Manley, for example, offers us forged pistons for the SOHC in .020- and .030-inch oversizes. Federal-Mogul has them in .010-, .020-, .030-, and .040-inch oversize hypereutectic and forged.

This is a primer to get you acquainted with Ford's SOHC and DOHC Modular V-8s. We're going to touch on these engines more in the months ahead, showing you how to make the most of Ford's new-generation overhead cam V-8 engines. We're hopefully going to build them, and we'll look into swapping them into a vintage Ford. Shortly, we will introduce you to Ford's new three-valve Modular V-8 in the new Mustang GT, F-150, and Expedition.

Pass the Shoe Horn

So how do you fit an engine like the 4.6 or 5.4 into your vintage Ford? If you're talking a compact or intermediate, you'll more than likely be looking at firing up the plasma cutter and ditching the complete front suspension for a Mustang II style front end or one of the newer late-model Mustang strut type front ends. Or you could graft a late-model Mustang front subframe to your classic Ford, giving you modern suspension, braking, and Modular engine mounting points. There's also cooling, wiring, and plumbing concerns to deal with.

From the classic Fords we've seen already fitted with Modular power, we can tell you you'll also have to figure out gas, clutch, and brake pedal mountings (most are using the '94-and-up Mustang brake-and-clutch pedal set), clutch actuation (cable or hydraulic), and more. Much of what you want to add to the car will determine complexity. We're starting to see aftermarket EFI wiring harnesses to wire up a Modular engine, but we've also seen some wild cars, such as DVS Restoration's MIB (Mustang in Black) project that retains the factory late-model Mustang antilock brakes, traction control, and cruise control. These additions will take a keen knowledge of wiring and a stack of factory shop manuals, so be prepared if that's your route. Depending upon what hardware you use, expect several trips to the parts store to match up hoses and fittings. Just like the 5.0 swap craze, as the Modular engines gain popularity look for swap kits, custom radiators, EFI fuel system hardware, and much more. While we've given you plenty of detailed information, your best bet at this time is to find a complete engine, crate engine or used, for your Modular-based project.

Check out Part 2 of our Modular Engines Explained series, where we cover the available cylinder heads, induction, and more for the Modular engine family.