Tom Wilson
June 1, 2005

Horse Sense:
Powerheads takes its name from its complete line of cylinder-head work. The company offers the full spectrum of early- and late-model small-block heads, as well as the current modular fair. It's sort of neat to see old Cleveland castings mingle with the overhead-cam variety.

Here be dragons," printed 15th century cartographers when they didn't know what was on the other side of an ocean, and it might as well be the slogan of small-block Ford enthusiasts when it comes to building modular V-8s. Raised on a steady diet of pushrods, the typical V-8 fan doesn't know a thing about timing two or four camshafts, and it's only natural to be afraid of what you don't know.

And, to be honest, there are good reasons to pause. Both the GT and the Cobra modular V-8s are not free-wheeling engines. In other words, if the cams and crankshaft are not correctly timed, the pistons will foul the valves, not to mention your wallet. And, Ford didn't do anyone any favors with its corporate acid trip of mish-mashed modular parts. Learning what parts are what and getting them from a vendor on time can be a trial. And, of course, there are more parts to keep track of, and few of them are inexpensive.

But if you have a modular under your hood, there are good reasons to learn the modular ropes. Once the modular V-8 has been demystified, you'll discover that, in many ways, the modular engine is not trouble, just different.

In fact, argues Ralph Pici at modular engine specialist Powerheads Performance, assembling modular engines is easier than building pushrod small-blocks. After following Ralph through some assembly work, we see what he means. With modular engines, the brainwork is in assembling the cylinder heads, and because enthusiasts normally buy their heads assembled, either new from Ford (PIs, for example) or as assemblies from tuners such as Powerheads, there's nothing to them save for taking the heads out of their shipping boxes.

That leaves the modular short-block assembly, then setting on the heads-another easy job-and, finally, timing the cams and crankshaft while installing the timing chains and associated front-engine dress parts. So setting up the cams is the unusual part. The rest is standard stuff such as screwing on the oil pan, water pump, intake, and so on.

Main Bearing Inserts
Here's one to watch for at the parts counter. Powerheads has determined there are four modular V-8 main-bearing inserts to watch for. Starting from the left in the photo they are as follows.
1)Clevite 77 MS-2202P. The only Windsor bearing.
2) Federal-Mogul 7292 MA. This Romeo piece is called a bi-metal bearing, but it actually seems to be an all-aluminum unit. Stock replacement part.
3) Federal-Mogul 148M. The second Romeo choice for GT engines, it features tri-metal construction. The lower insert is guttered for increased oil flow.
4) Federal-Mogul 149M. The Four-Valve or Cobra bearing. The lower insert is guttered, and the locating tangs are different.

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All the inserts with open grooves are upper inserts. The plain, or less grooved inserts are lowers. The standard Ford aluminum bearings use a lower insert that is 100 percent plain. The 148M and 149M bearings use lowers that are guttered with a gradually shallower groove on each side. These are Yates-style, for more oil flow at higher rpm. Powerheads says the stock Ford aluminum bearings are best for naturally aspirated engines. They fit the crank beautifully, and often 100,000 mile crankshafts come out looking better than stock because the bearing/journal interface has polished the crank all that time. Forced-induction engines do better with the physically more robust tri-metal (steel shell) bearings. In any case, you'll throw less of a rage when the tangs and materials line up when you go to lay the crank.

What we've done here is tag along while Powerheads assembled engines, then presented those portions of assembly unique to the modular V-8 in the photos and captions. As we quickly saw, there really is nothing to be scared of in the mod motors as far as putting the parts together. Ralph says he'd much rather assemble a modular than a small-block these days because the small-block requires assembling and adjusting the pushrod valvetrain, while the modular assembly is not much more than tightening a bunch of bolts. We agree.

We're also showing a few details of the Windsor/Romeo differences as they seem appropriate to engine assembly. We should also report Ford has been working on standardizing the W/R situation in the last year or so, mainly in favor of Romeo parts, it seems. Still, there are plenty of modular parts nuances to learn.

Finally, before we jump into the photos, let us stress the importance of following the torque specifications and especially the torque sequences when assembling modular V-8s. From a strength standpoint, mod motors are an eggshell built around the crankshaft. The majority of stresses in the engine are transferred deep into the block, to the main bearing webs and bulkheads. This is especially obvious with the head studs, which are rather long and pass through the cylinder block's deck to thread into the main bearing web area. This also explains the deep-skirted block design-most of the engine stresses are passed around the crankcase, rather than being spread through the deck, cylinders, water jacket, and then the main bearing bulkheads.

This main-bearing-centric design allows a lightweight block, but it also means you can twist it into a pretzel with the wrong torque sequences or specs. Use an appropriately sized torque wrench and follow Ford's sequences to the letter. Such information is available in various service manuals, and Powerheads said it was working on a pamphlet of assembly highlights to package with its engines and assemblies. So far, the company has done an unusually thorough job of assembling all sorts of detailed, hard-to-find modular knowledge for its own use, so a quick checklist of things to watch for from them would be welcome.

In the meantime, this article can get your mod-think primed to time.

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Aluminum GT
You may have noticed one engine in our photos uses an aluminum block and Two-Valve cylinder heads.

Powerheads reports this is an easy combination to build, with no major issues. You'll want to consult with the company on details of your particular engine for such a swap, but it does sound like a great way of aiding handling via reduced front-end weight.

Romeo vs. Windsor
Most Mustang enthusiasts know Ford has built the "same" 4.6 V-8 in both Romeo and Windsor configurations (the names come from the assembly plants). Exactly what engines were used in what vehicles is an open question. Patterns have emerged, but occasionally it seems Ford used whatever engines it had at the time. Powerheads figures all Mustang GTs are Romeos with the exception of '99s and '00s, which are Windsors. All Four-Valve Mustangs are Romeos; many or most truck engines are Windsors.

There are multiple detail differences between Romeos and Windsors, and these details have changed over the years. While maddening nonessentials such as the number of bolts in the valve covers are part of this, the big difference is in main bearing cap retention. Romeos use a threaded sleeve for the side bolts; Windsors feature a nonadjustable peg or pin arrangement.

Ford has been consolidating this incredible engine mess to arrive at a single, modular V-8 specification. The standardized engine is mainly Romeo, including the main bearings, but a few Windsor details are included. Powerheads builds mainly Romeos, as it prefers the adjustability of the main bearing attachment, and that is the replacement block available from Ford.

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