What were you doing in 1991? The Gulf War was waged, Rodney King got a beat down, the Pittsburgh Penguins won their first Stanley Cup, the Minnesota Twins won the World Series, and Ford Motor Co. dropped the first 4.6L single overhead cam, two-valve-per-cylinder modular V-8 engine into a Lincoln Town Car, thus beginning its phasing out of the pushrod V-8.
The early mod motor was almost universally panned. As it rolled out across the other FoMoCo car lines, the critics became louder and more numerous. The most vociferous among them were Mustang owners, who largely despised the engine. The '96 Mustang, the first to boast mod motor power, carried the same 215hp rating as the previous year's car, the last with the venerable Five-Oh engine, but you wouldn't know by driving it. The power delivery was differ-ent from that of the outgoing pushrod engine, it had less low-end grunt, and it needed to rev higher to reach its powerband. As the Europeans are quick to point out, this situation is intolerable to Americans who demand the instant torque needed to win stoplight drag race wars. Mod motor Mustangs were getting their asses handed to them at intersections all across the country by smug Camaro and Firebird owners who had 275 hp from 350ci LT1s.
Ford responded by rolling out versions with more horsepower, but the company was a little too slow in doing so, and the unfortunate gutless, complicated, expensive stigma surrounding this engine remains in some segments to this day. One could argue that Ford may have prevented this by introducing the 280hp four-valve version first and putting it straight into the Mustang. Such was not the case, though, and the engine has struggled to gain the hearts of the masses. Compounding the problem, the aftermarket was slow to embrace the modular V-8, and that has kept many enthusiasts from building these engines. With the introduction of Trick Flow's two-valve heads, we think the tide is changing and that we'll be seeing more of the mod motor in performance applications.
This article is an overview of the performance potential of the mod motor. We received expert advice from the guys at Modular Mustang Racing (MMR) and Modular Head Shop. They gave us a few build options to consider and warned us of some traps to avoid along the way. This engine is a worthy platform and is capable of making an impressive amount of power. Let's investigate.
 Modular blocks are cast in...  Modular blocks are cast in either aluminum or iron at either the Windsor, Ontario, or Romeo, Michigan, plant. There are a few differences between the Windsor and Romeo blocks, but the cylinder heads all interchange. Look for a W cast into the boss near the starter to know if your engine came from Canada or not. Regardless of the material used, any modular block is good to at least 800 hp. That means the block in the taxi rotting in the corner of the junkyard has just as much performance potential as the block in the '03 SVT Cobra, the so-called Terminator engine. The blocks use a deep skirt design with cross-bolted main bearing caps. From the factory, they are a lot stronger than a 5.0L block. They have a reputation for longevity, too. Our sources have seen modular engines with 500,000 miles that still meet the factory specs. All 4.6 blocks can use any 4.6 crankshaft and rod bearings, but the Windsor and Romeo blocks use different main caps and bearings. |  The two blocks also have different...  The two blocks also have different reinforcement ribbing in the lifter valley. Unlike the Windsor style shown here, Romeo blocks have smaller ribs running across the valley from side to side. |  The 5.4 blocks are immediately...  The 5.4 blocks are immediately recognizable by their taller decks. The machined pad above the core plug shows the extra material. The deck on 4.6 blocks is nearly even with the top of this core plug. |
 Aluminum blocks are desirable...  Aluminum blocks are desirable for their weight-saving advantage over the iron blocks. Of the aluminum blocks, the earlier ones cast in Teksid, Italy, are reported to be the best available, aside from the mid-engine, dry-sump Ford GT block. This is a customer's Teksid block being assembled at MMR. It is recognizable by fewer ribs in the valley than in the later Windsor aluminum blocks. |  The Teksid blocks were used...  The Teksid blocks were used in all 4V 4.6 engines from '93 to '98. We've seen several in the junkyards and even more selling for cheap on eBay. Make a beeline for the nearest Lincoln MK VIII, pull the engine, and get ready to make 1,000 hp. These blocks were also in '96 to '98 Mustang Cobras. | |
| Specs |
| |
4.6L Engines |
5.4L Engines |
| Cubic inches |
281 |
330 |
| Bore |
3.552 |
3.552 |
| Stroke |
3.543 |
4.165 |
| Bore spacing |
3.937 |
3.937 |
| Deck height |
8.937 |
10.078 |
| Main journal diameter |
2.657 |
2.657 |
| Rod length |
5.933 |
6.658 |
| Bare block weight, iron |
154 pounds |
| Bare block weight, aluminum |
86 pounds |
Note that the bore and bore spacing are the same for the 4.6 and 5.4. Therefore, any cylinder head will fit on any block. You do need to check the head gaskets, though. The oil holes may be in different locations and could cause oil to leak into the coolant. Your best bet is to use Ford Racing's head gaskets.