5.0 Mustang & Super FordsHow To Engine
Building a 1,627 HP 2007 Ford Shelby - 7-Second Screw
Mark Meiering is the first to take a blown GT500 into the 7s
He considers this a low-compression engine at 12:1—alcohol is forgiving of high cylinder pressures—and everything is coated for reducing friction or as heat barriers. The rings are file-fit Total Seals with a tough-as-nails stainless steel upper ring. The engine was broken in on Pennzoil 5W30 mineral oil, then run on frequently changed synthetic Lucas 5W30 due to oil dilution by the rich alcohol mixtures.
John notes he's seen 50hp gains from increased header size at this power level, and Mark's engine benefits from enlarged headers. He also notes the Mustang/Shelby body accommodates only a small rear tire and thus can't handle excessive torque. So John has tried to shift the torque peak higher by widening the overlap and extending the exhaust duration in the custom camshaft grinds.
For another look at this family of engines, check out our inside look at John Mihovetz's 4.6 program (Mercury Cougar Cobra Hybrid - Mad Motor-World's Quickest Modular). A few details have changed since that '09 article. John's switched to methanol and a different chassis; it makes an additional 500 hp since our chronicle—but the general idea applies to Mark's larger 5.4-liter engine.
Speaking of articles, comparing this story to our earlier article on the Kenne Bell 3.6 supercharger as run on Mark's engine, some notable configuration changes have occurred leading to the 7-second run. Most importantly, the giant Kenne Bell Mammoth inlet was discarded in favor of a pair of even larger rear facing throttle bodies. They aspirate unimpeded from the high-pressure area at the base of the windshield, an arrangement we've long thought superior to sneaking air through holes in the radiator support or fenders.
In preparation for the 7-second attempt, the engine was dyno-tested and the car hit the chassis dyno several times. Even though most of the dyno work was quick tuning checks at reduced ignition timing and other brief, not full-rpm runs, we did get a good clue of what the engine produces: a documented 1,627 hp at the flywheel and 1,225 hp at the tires. As we just hinted, the combination makes north of 1700 hp at the track, as that's the only place the engine has been run with something approaching a hot tune. There should be a little more in it given a cool day, and Mark suspects there's a 7.60 timeslip under ideal conditions. When it does, Mark will follow his usual drill of leaving on the transbrake at 3,500 rpm and running it out the back door at 8,400 rpm.
The engine is perfectly happy; overall it's a smooth ride with the new torque converter. Things to work on are weepy head gaskets, something of a constant at this power level, and something Accufab can cure with its dry-deck trick which separates the water path between block and heads, with no water passing through the head gasket interface.
That done, we think Mark might be content to rest a bit. The road to the 7s has been longer, and more labor and fiscally intensive than he really enjoys. A man of the street, Mark finds the racer's reality tiresome. The constant upgrading, compounded by whatever custom work required because you've upgraded everything it bolts to … it's not the street with its cruising and quick blasts. But he's got a solid 7 in his pocket and it would be nice to shave a tenth off that…
On the Dyno
It's rare that we get both chassis and engine dyno data on the same combination. Unfortunately, the rpm range crossover is minimal, but that brief meeting of data does show that there is a bit of drivetrain loss when you install an engine in a Mustang. In either case, Mark's Shelby is putting down huge power.
In either case, Mark's Shelby is putting down huge power.
|Chassis Dyno||Engine Dyno||Difference|
Mark's ticket from his test session at Famoso dragstrip in Bakersfield, California, is more impressive when you realize it was run in 90-degree weather.