Muscle Mustangs & Fast Fords
Modular Mustang Racing 850 Stroker Engine Build Part 2
Late Nights And Tire Smoke Lead To A Stroker Engine And 12-Second Runs In Project Silver Stealth Stang.
Silver Stealth Stang screamed on the chassis dyno, and its initial output was 279 rwhp with low timing. Radovich dialed in the air/fuel ratio and tried various timing settings. He started at 22 degrees and went as high as 27 degrees. "The car produced the best power with 24 degrees. Going higher or lower resulted in a loss of horsepower. It was a minimal loss, but still a loss," stated Radovich. He also noted that the stock injectors were providing enough fuel, but if we were to add an intake and full-length headers, then a larger injector would be required. The 19-pounders were nearing their capacity in the upper rpm range. As for power, the car registered a best of 285 rwhp and 294.31 rwtq--impressive for a Two-Valve engine that doesn't benefit from forced induction.
As with all of Silver Stealth Stang's horsepower mods, dragstrip testing was required to finish off the article. Englishtown awakened from its winter slumber, and the track management applied a healthy dose of traction compound for our private track rental. The looser torque converter and extra power under the hood forced us to add some sticky tires out back. The Nitto 555 tires barely worked on the street just leaving from idle. We bolted on a pair of Mickey Thompson 26x12.50-inch ET Street DOT slicks. The tires are mounted on 17-inch wheels and tire pressure was set at 12 psi. The temperature at race time was a spring-like 63 degrees. Miele performed a smoky burnout for the cameras and brought Silver Stealth Stang to the starting line. The green light popped and Miele left cleanly, covering the first 60 feet in only 1.81 seconds. On the top end, the silver Stang streaked to the finish line with a 12.85 at 106 mph. Launch rpm was 2,000 rpm and Miele simply matted the throttle at the green. "The transmission shifted early on the 2-3 upshift," was his comment immediately following the run. He backed up the 12.85 with a 12.87 and a 12.90, all at 106 mph. Miele continued: "I think the car could have gone in the high 12.70s if the 2-3 shift was a few hundred rpm higher." Amidst the excitement over the 12-second runs, Miele forgot to drive over the scales. The car is hefty thanks to the spare tire in the trunk, large front brakes, and heavy 18-inch front wheels.
From the outset, Lutton told us the engine was capable of making similar power to the '03-'04 Cobra Terminator. Armed with that information, those cars regularly put down 340 rwhp on the Radical Racing dyno in bone-stock trim. Why didn't Silver Stealth Stang achieve that mark? The answer lies in the slushbox Ford nicknamed the 4R70W. Using the popular 15-percent conversion from stick to auto, our calculator showed a Terminator engine should make 289 rwhp if backed by an auto. The engine barely has 150 miles on the odometer, so we think once it's broken in, the power will rise about another 5-10 rwhp, bringing it inline with our estimate. Editor Smitty told us that he has personally compared the auto and stick transmission in a back-to-back test with an old project car. He saw a loss of 50-60 rwhp, which backs up our guesstimate.
The final tally after several long days and a trip to Englishtown netted us near 300 rwhp and solid 12-second runs. There is certainly more power lurking under the hood, and in the coming months, we plan on adding bolt-on parts such as a larger intake manifold, a MAF sensor, a throttle body, 30-pound injectors, and whatever else we can in order to get more out of Silver Stealth Stang. Our work on the modular family's red-headed stepchild isn't done yet. Stay tuned.