Eight down, two to go: adding two cylinders to Ford's 4.6-liter V8 not only proves its modularity, but gives the automaker a flexible, powerful and unique V10 that has many potential uses.

When Ford rolled the Cobra Concept out at the 2004 North American International Auto Show, many observers stopped at the billet-like exterior styling. Most overlooked the importance of engine under the hood, a Modular V8-based V10 displacing 390 in.[.sup.3] It was the second time a Modular V10 had appeared in a recent Ford concept car--the first was the 427 in.[.sup.3] V10 that powered the aptly named "427 Concept"--and a clear indication this engine isn't about to lay down and die.*

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The whole V10 program started as an after-hours project based around the 4.6-liter low-deck Modular V8. Unlike the high-deck V10 currently offered in Ford's heavy-duty light trucks, this engine fits anywhere the Modular V8 does. The smallest displacement version, one of the original engines built, displaces 351 in.[.sup.3], and fits neatly under the hood of a Mustang test car. You have to count the plug wires to make sure all ten cylinders are there. "The engine is in the stock location," says Greg Coleman, a technologist at Ford's Powertrain Research & Advanced Engines. "The rear face-of-block is in the production V8 location, as are the radiator support and radiator, and the engine is exactly 100 mm longer than a 4.6-liter four-valve V8 with the same height and width." Challenge Coleman on the effect the increase in length might have on crash performance, and he is likely to quote a lengthy list of cars currently on the road with less space between the leading edge of the vehicle and the front of the engine.

Meanwhile Kevin Byrd, V10 project lead, Powertrain Research & Advanced Engines, answers concerns about fuel economy almost before they are asked: "Not only is there a more than 60-lb weight savings (compared to the iron block 5.4-liter Cobra R V8 from which the team borrowed the head design), because there are two more pulses per revolution, we probably can calibrate this engine to produce a net fuel economy increase." Currently, the 351 is running a rudimentary ECU calibration.

"The camshafts run the same profile as the 2000 Mustang Cobra R," says Coleman, "because they are matched to that combustion chamber and port configuration, which we stretched to create our heads." The connecting rods are based on the design used in the "Terminator," the supercharged Mustang Cobra, and the intake manifold was hand-fabricated from old Cobra R castings. Because the crankshaft--milled from a billet of 4340 steel--borrows the V8's design, the V10 has firing pulses every 54[degrees] and 90[degrees]. Lack of budget means two controllers are used to run the V10 as independent inline five-cylinder engines, and the engine feels slightly coarser as you might expect. However, it exudes an unmistakable American character no other engine can match, and has grunt that just won't quit.

With 430 hp at the rear wheels in this, admittedly, rough state of tune, the 557-lb. (dressed) 351 V10 is the most powerful naturally aspirated engine in the Ford stable, and one with plenty of room for development. Coleman and Byrd, for example, would love to develop 3-valve heads, and explore the gains that can be made with dual (intake and exhaust) cam phasers. "You could phase the cams for a broader torque curve [currently 440 lb-ft at 5,500 rpm], and still stretch it out toward the 7,500 rpm limit to get the horsepower," says Byrd. "There's a whole bag of tricks we could throw at it."

Putting the V10 into production would follow much the same process used to make the prototype engines, only this time the CAD data, not the cores used for casting the block and head, would be cut and pasted, making the V10 a relatively inexpensive engine to source on a total systems-cost basis. Ford's flexible production machinery should be able to handle the V10's block and heads, while the camshafts, crankshafts and intake manifold would be unique parts. A niche application, on the other hand, would be tooled and sourced like a prototype to keep investment costs in line for the lower volumes. "Probably the biggest hurdle," cautions Coleman, "would be that the transmission engineers would faint, but until they start coming up the street with pitchforks and torches ..."

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Ford V10 Specifications

                      351 MUSTANG               COBRA CONCEPT

Description:          90[degrees] V10           90[degrees] V10
Block/Head material:  Aluminum                  Aluminum
Displacement:         5,751 cc/351 in.[.sup.3]  6,393 cc/390 in.[.sup.3]
Redline:              7,500 rpm                 7,500 rpm
Bore/Stroke:          90.2 mm/90 mm             93.0 mm/94.0 mm
Compression ratio:    10.5:1                    10.8:1
Horsepower:           500 @ 6,750               605 @ 6,750
Torque:               440 lb-ft @ 5,500         501 lb-ft @ 5,500

* If the Cobra reaches production, Ford will need the V10 to avoid the lowsuits, media sniping and acrimony like that which followed Jaguar's decision to replace the concept XJ220's V12 with a twin turbo V6 when it went into production.

RELATED ARTICLE: DRIVING THE 351 MUSTANG

Finesse is not a word that comes in the same sentence as, "Let's see what this baby will do." Mostly because before the words leave your lips, the Mustang V10 is flying down the road at surreal speed. Almost instinctively, the mind starts searching for an adequate descriptor. The only one that makes sense is "magnetic" due to the Mustang's ability to draw the cars and trucks in front toward it almost instantaneously. Yet this is only one of the V10's talents. It also can tool around in higher gears with reserves of torque on tap, cruise quietly at posted speeds, and scream with a haunting and distinctively American howl when prodded. More importantly, however, it does all of this without upsetting the handling balance of the car. The V10 Mustang goes around corners just like its V8 little brothers.

Look past the rough edges of this prototype, and you see the V10's sizeable advantages: low investment cost, a short development process, no center of gravity change, ease of installation, power and economy, a flat torque curve, few production or assembly hurdles, multiple applications, a segment-unique architecture, etc. And while the transmission engineers might not want to think about adapting their current offerings to the torque output and rev limit of the V10, mating a six-speed automatic to this engine and placing it in vehicles like Lincoln's Navigator and Town Car, or dropping it in a high performance Mustang, seems like a slam-dunk. One that would put Ford well ahead of the competition in the image race.

RELATED ARTICLE: V10

VALVETRAIN: Based on Modular 4V V8 valvetrain with Cobra R lash adjusters and roller finger followers. High-performance cam profiles and hollow-stem valves.

DRY SUMP (COBRA CONCEPT): Internally driven from a location within the oil pan. Chain drive is common with Duratec 20 V6 oil pump. Threescavenge G rotors, remote settling tank/oil reservoir.

CYLINDER HEAOS: Design based on 5.4-L 4V Cobra R heads, and produced by combining production sand cores. Modified water jacket for improved coolant flow.

BLOCK: Based on 4.6-L Modular V8, produced by combining sand cores.

ROTATING ASSEMBLY: Common pin/odd firing crank. Production 4.6-L "Terminator" connecting rods. Mahle pistons.

By Christopher A. Sawyer, Executive Editor