Muscle Mustangs & Fast Fords
1993 Ford SVT Cobra Mustang Project Stolen Goods - Stolen Goods Recovered
Our '93 Cobra Project Mustang Gets Its Fangs Back.
Shifting And Twisting
We've covered the suspension, brakes, and engine, but the car still wasn't going anywhere without a transmission and rear axle. Having just installed a six-speed in the ProCharged Pony, MM&FF's supercharged Fox GT, we had a spare T5 handy and thus called Tony Sarvis at Astro Performance Warehouse. A trip to APW's home in Tavares, Florida, ensued, and a few hours later I was headed home with a virtually bulletproof A-5 transmission. In addition to the beefy internals, I opted for the road-race-spec Fifth gear, which features an 0.79:1 Overdrive ratio.
Mating the trans to the engine is Centerforce's light metal clutch and pressure plate, as well as its aluminum flywheel. The clutch's lightweight con-struction drops significant weight from the overall rotating mass, and it offers plenty of clamping force with an easy pedal effort. Remember, this Mustang needs to be driver-friendly, and we didn't want to be gear-jamming, Peterbilt-style. Centerforce had just what we were looking for.
After spending a few hundred miles behind the wheel, I must say that I dig the close-ratio Fifth gear, but truthfully, cruise rpm is a little too high for my taste, even with the mild 3.55 rear-gear ratio. At 70 mph, the tachometer is hanging at around 2,800 rpm, and since Florida's 70-mph I-75 corridor is my main access to most racing venues, not to mention my place of employment, there may just be a T-56 swap in Stolen Goods' future. The good thing is Astro Performance can hook you up with one of those, too, if you find yourself in a similar situation. If you're limited to the normal 55-mph interstate system or restrict your civilian driving to around town, you'll have no problem with the A-5 unit.
Behind the A-5 five-speed gearbox is a typical 8.8 rear axle. Since the main caps were missing from the original housing, we procured a used one from Rusty Acres Automotive. Rusty Acres is a Ford auto salvage business located in Jacksonville, Florida, and it dropped the 8.8 assembly off at nearby HP Performance in Orange Park, Florida, for a rebuild. Reider Racing came through with a complete rebuild kit, including new axles, bearings, seals, and shims, in addition to the 3.55 ring-and-pinion gearset. After consulting with Maximum Motorsports' Chuck Schwynoch regarding differential choices, we opted for the Torsen T-2R, a torque-biasing unit that is preferred for road racing.
Crank It Up
The first time Stolen Goods fired up, it crackled with vigor and settled into a perfect idle. The lightweight rotating assembly revved effort-lessly, and all of the Boss 347 engine's vitals looked great. Things were certainly looking good.
To maximize power output, we took the car back to HP Performance to have a custom chip burned. Using SCT's software and plug-in chip to tweak the processor, HP's Tony Gonyon did an excellent job making sure Stolen Goods fired up without issue every time. He also made numerous changes to optimize cruise and full-throttle conditions.
Our original plan for Stolen Goods called for great driveability and lots of torque to take advantage of the 3.55 gear ratio and give us extra grunt for getting the Cobra off of the corners. With that in mind, we didn't expect the 347 to make balls-out power figures. Rear-wheel horsepower came in at 358; it also twisted the dyno drums with 376 lb-ft of torque. Going with a 12-percent drivetrain-loss estimate, that puts us a tick over 400 hp and 421 ft-lb of torque at the flywheel. I can report that Stolen Goods has plenty of bite all the way through the powerband.
A week after the tuning, which included several dyno pulls, Stolen Goods was at the alignment shop where it promptly broke a rocker-arm stud during the test drive. A call to Summit Racing had another rocker stud in the mail so that we could venture to Gainesville Raceway in Gainesville, Florida, for some dragstrip drama. For two hours we drove through a downpour before the track event was finally can-celled, and on the way home, we suffered another broken rocker arm in addition to toasting the mass air meter because of the excessive amount of water that had gotten into the inner fender area.
Great minds were organized, and the consensus was that the rocker-arm issue was a result of the pushrods being too long. A difference of 0.15 inch is seemingly all it took to turn our project car around and make it the hissing serpent we expected it to be. While we took the time to carefully place the rocker-arm roller tip on the valve stem during the engine's assembly, we hadn't been careful enough.
After swapping out our 6.85-inch-long Comp Cams Hi-Tech pushrods for a set of 6.700-inch pieces and having Chris Skotnicki at Professional Mass Air Systems send us another meter, we now have several hundred miles on the odometer and a couple of full-throttle, quarter-mile passes under our belt without a hint of trouble from our 347ci powerplant. Speaking of which, we were able to get in just two quarter-mile passes before this story's deadline, and here are the details.