The billet crank spun by those slugs is an interesting piece, again bearing no resemblance to the one in the truck 6.8 V-10. We'll let V-10 project lead Kevin Byrd describe it. "The 6.8 truck crank is a split-pin crank, like you'd find in a 60-degree V-6. [For the 5.8 V-10] we went to a common-pin design based off the Cobra crank, only instead of four pins, we have five. The crank is set at a 72-degree pin offset, but when you put that in a 90-degree block, it doesn't line up to a 72-degree firing. It ends up to be a 90/54, so you get that odd-fire sound, but it blends together beautifully."
We agree that the sound is both appealing and distinctive, unlikely to be mistaken for any old V-8, even though in the Boss 351 it's thoroughly muffled with four mufflers, along with two metallic and two ceramic catalytic converters. In one of the more challenging aspects of construction, five-into-three-into-one headers were bent up with no particular emphasis on performance, rather just something that would fit (using a tubular K-member made it all possible and took further weight off the nose).
Because of the common-pin, odd-fire crankshaft, the project crew couldn't just wire it all up to a single EEC V from the 6.8 V-10 (an engine that uses a split-pin, even-fire crank with balance shaft). Instead, they had to use two such processors, each one calibrated to think it's controlling an inline five and not knowing the other one exists. This requires duplicate crank, cam, mass-air, and other sensors, and it also necessitates the pair of 70mm throttle bodies that feed into the impressive-looking, black intake-plenum chambers. Through custom runners, these supply a lower intake that is a narrowed (that cut-and paste-thing again) Cobra R casting.
Carrying on with the miniscule budget theme, with the engine assembled-but never once tested on the engine dyno-it was decided to shoe-horn it into a well-used silver '99 GT unibody that had previously seen duty as the test-fit mule for a prototype '00 Cobra R 5.4 (explaining its bulging R hood, which is not needed to clear the short-deck V-10). We suppose the thinking was that if they could squeeze the V-10 into a Mustang, it would fit into practically anything. This job of wrapping the car around the engine fell to powertrain systems supervisor Jim O'Neill, and it turned out to be easier than you might think. Far as we know, he never even reached for a sledgehammer. Engine-to-firewall spacing remains identical to a production 4.6, and the additional 4 inches of length up front is, surprisingly, easily accommodated in the Mustang engine bay (all you state troopers out there, imagine how well this thing would fit in a Crown Vic Police Interceptor).
Knowing it was destined for a hard life of trying to convince management of its merits, the V-10 was backed up with a T56 six-speed and a 9-inch rearend (currently outfitted with 3.82 gears). As with so many others, these were pieces the crew was able to scavenge off the shelves of the Powertrain Research & Advanced Engines garage. A bit more calibration fiddling made it pleasantly driveable, and they eventually rumbled over to the Dynojet at Livernois Engineering to see what kind of power their little 10-pot dictator wielded. The project immediately proved its worth with 426 hp at 6,500 rpm and a nice, even 400 lb-ft of torque at 5,200.
"The whole car," Kevin Byrd summarizes, "was a process of a handful of guys just being as absolutely creative as possible, from making it, to making it run, and scrounging parts."