STAGE WRITE
I’M REALLY excited to tell you that drag racer Dave Sheehy recently broke out with a 10.923@125mph on a 10.95 dial-in. Why would breaking out of your dial-in be a good thing? Because to the best of my knowledge, it’s the first time a street-driven, late-model naturally aspirated 5.0-litre Mustang has run 10s in Australia.
The best part about this story is that the 520 Moroso horsepower of Dave’s Mustang can be duplicated for around $2500, if you have a new 2018 Mustang equipped with the GT350 manifold as standard, or $7500 for older models. That’s an insane 1.72hp per cubic inch from an unopened, stock four valve-headed factory Ford Coyote motor.
I went around to Dave’s house and photographed the blue Mustang exactly as it had been driven back from Palmyra after running its first 10s. How was his achievement possible with just a few bolt-on parts?
First of all, if all you did was put E85 in the tank but made no other changes, that would straight way give you an extra 10kw, or 15kw after tuning. Dave has never seen another engine respond so well to a tankful of E85, and it works out about the same cost per kilometre as using PULP. The real benefit of the 85 per cent ethanol blend is the 107-octane rating, which allows the timing to be increased.
The only physical changes to Dave’s stock Coyote motor are a GT350 manifold, Xforce stainless extractors, TOG exhaust and 1000cc 100lb injectors. The Mustang only needs 47lb injectors plus a tune to run E85, but Dave has an Edelbrock 2650 supercharger waiting under the bench – more on that later. The oil pump, sump, cam, heads and everything else in the 5.0-litre motor are exactly as supplied from Ford.
The only mods to the suspension are to the rear coils, with six inches cut off the passengerside coil and 4½ inches off the driver’s side. The front and rear shocks are factory, along with all control arms.
The rear 17x10 Enkei wheels need an alignment, so there’s possibly another tenth there. The rear tyres are old load-rated streetlegal Mickey Thompson 275x40x17 radials. There is no sidewall give, so Dave has to soft-launch the Mustang at 2000-2500rpm. That’s made possible by a Circle D 4C 3500rpm lock-up stall converter, which costs around $2000.
The 6R80 gearbox is absolutely standard except for the tune. The standard transmission program has transbrake capability, but that feature has been turned off for Australian Mustangs. Dave hasn’t used this feature as he’s worried about breaking parts. By flashstalling the converter off the footbrake, there’s less shock load on the driveline; Dave’s having enough trouble hooking up the Mustang on a sticky track without a line-lock or transbrake.
Dave’s Muzzy has also been put on a diet. The stock big front brakes were too heavy, so they’ve been replaced with lighter 12-inch Wilwood discs and calipers. The front sway-bar has also been removed and the front wheels are now Race Star Industries 17x4.5 items fitted with 26x17x4.5 M&H Racemaster tyres. The rear seats were removed and the front seats replaced with a lightweight racing seat. All-up weight with Dave included is 3500lb (1590kg).
Dave told me about issues with the stock oil pump. The Coyote’s oil pump will last forever under normal operation, but if you hit the rev limiter it can fracture the gears, which explode out the side of the pump. Dave paddle-shifts at 7800rpm with the rev limiter set at 8500rpm, and at those revs he could destroy a stock oil pump and hurt the engine. His solution was to fit billet oil pump gears and replace the bottom cam chain sprocket with a billet sprocket. While he was at it, he replaced the stock sump with a GT350 version, which holds more oil under the windage tray and stops aeration.
Dave’s ’Stang is expected go 10.7s at the next meeting, with a few other changes about to happen. There are two new manifolds on their way for testing to see which one works out best. After that, the aforementioned Edelbrock supercharger will come out from underneath the bench. Dave’s goal is to have a supersmooth 700-750hp street car that can run low 10s all day at 135mph. His days of climbing in and out of rollcages are over!
You can find plenty of details and step-bystep progress on Dave’s Mustang on the CPV Tuning Facebook page, along with videos of passes at the track.
TO THE BEST OF MY KNOWLEDGE, IT’S THE FIRST TIME A STREET-DRIVEN, LATEMODEL NATURALLY ASPIRATED 5.0-LITRE MUSTANG HAS RUN 10S IN AUSTRALIA