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1991 GMC Syclone - Tycoon

Will This be The World's Fastest SY?

Rick Jensen Oct 1, 2005

Step By Step

The PT-91 turbo utilizes a 7-inch inlet, 3.5-inch outlet, and an Innovative Turbo 51mm Indy-Gate wastegate.

The rear window was replaced with Lexan in order to cut it around the rollcage; meanwhile, the rest of the glass is factory, including the electric windows. All of the sheetmetal is factory as well, repainted and massaged by Golecki Customs. The only addition to the exterior is the adjustable wing created by Competition Fabrication for high-speed stability.

This award-winning engine bay features coated headers and intake tubing from LO-KO Performance Coatings. The splashes of red come from an MSD distributor and 10mm spark-plug wires. The flawless paneling and firewall can be credited to Competition Fabrication, who also fabricated the headers and tubing. And by the way, the 311-inch V-6 should make about 1,200 horses!

The carbon-fiber inserts and Creative Auto Tops & Interiors fabric helped Jason win Best Interior at the Detroit Autorama. Autometer Pro Lite gauges, a B&M Hammer shifter, and an Innovative Turbo boost controller also did their parts in addition to being quite functionally necessary. All the standard safety equipment for an 8-second race truck is still present though, including RJS five-point harnesses, a window net, a Simpson 10-foot chute, and a Safecraft 3-pound billet extinguisher.

Nestled under the carbon-fiber bed cover and aluminum wheeltubs are three Derale 10x16 engine and trans coolers with 650-cfm fans.

The rolling stock consists of Weld Magnum wheels measuring 15x4 and 15x15 with Mickey Thompson Sportsman skinnies and 33x19.5 tires for the street.

Competition also fabricated this scoop for the turbo to feed it fresh air, and another scoop can be found underneath the car to channel more air onto the intercooler. A custom Griffith aluminum radiator, Spal 2,200-cfm electric fan, and Mezeire 55-gpm remote electric water pump were all used to keep the monster at bay and circumvent the tight confines created by the front mounted turbo and intercooler.

If there were ever a Shogun of GMC Syclone owners, it would be Jason Leach from Crystal Lake, Illinois. Like any good Shogun, he has the spoils to back up his power-only his currency is made not of gold, but in Syclone and Typhoon paraphernalia. In fact, he had to devote a large section of his garage to storing a list of memorabilia including 600 Johnny Lightning model trucks, 400 magazine articles mentioning the rare pickup and SUV, product literature, brochures, original GM blueprints, service manuals, emissions records from the factory, shirts, hats, and even shoes. The real jewels of his collection, though, include '92 Typhoon No. 0022 purchased used in September 1993, a '91 prototype Typhoon maintained in original condition with 29,000 miles on it, and brightest of them all--a tube-chassis Syclone that he purchased new in November 1991 (No. 2158).

Jason's love of Syclones dates as far back as the Oct. '90 article in Hot Rod introducing the hi-po pickup. He couldn't believe this little truck could run with the big-dog ZR1 Corvette. "Ever since I saw that article I have been enamored with the trucks and I couldn't believe the performance for the dollar. It was a high-performance truck that actually performs," said Jason. Performance comes at a premium though, as it only keeps you yearning for more. Before he knew it, he was ordering a larger turbo and bolt-ons, and shocking Corvette owners soon became his favorite pastime. No one could believe a little V-6 was capable of that kind of power. After he had renowned Syclone engine builder Guy Reffett of Rockford Racecraft build him an engine, Jason thought he would really turn some heads. Unfortunately, although the engine was capable of running 10s, the 700-R4 was not, and it soon failed.

At the prospect of already having to drop in a Turbo 400, Jason decided that 9- and 10-second streetcars were becoming all too common. "I wanted to take it to the next level." And upon meeting Dave Daunheimer of Competition Fabrications, it was readily apparent just who could get him there. "I was truly in awe of Dave's work and the quality of welds that he had made on his own 6-second dragster, as well as some of the other cars around the shop. I had originally intended to look around for a while until I found someone that was just right, but I didn't bother after that." After talking over his plans with Dave, building a tube chassis became a necessity for safely running in the 8s. "It broke my heart to do it, but I had already heavily modified the car and I knew in the end it would turn out better."

Now that things had gone back to the drawing board, Jason contacted Rockford Racecraft to build another engine, only this time the goal was to build the biggest and baddest turbo V-6 motor conceivable. A GMPP Bow Tie block was taken to its limit at 4.125 bore and the stroke bumped up to 3.875. Only the finest bottom-end components were used from a Moldex forged crank to Oliver 5.85-inch forged rods, Speed Pro bearings, Total Seal gapless rings, and JE forged pistons. A set of Bow Tie cylinder heads was shipped off to Flow Technologies Inc. where an ungodly amount of man hours was spent porting the 18-degree aluminum heads. After being fitted with a Ferrea 2.15 intake and 1.625 exhaust valves, PSI dual racing valvesprings, Teflon valve seals, and COMP Cams titanium retainers, the heads were now flowing almost 330 cfm at .600-inch of lift. Rockford mated the heads to the 311ci short-block, sealed by Cometic 3 layer steel and graphite head gaskets and installed the largest cam they had ever done. "Many years of R&D combining lobe separation with duration, along with some help from COMP Cams, went into the design of this custom grind," said Guy Reffett of Rockford. The whopper measures .673-inch lift and 262/267 duration at .050. "This is the wildest motor we have ever done, and it may be the wildest in existence." That may be a shallow compliment coming from your average local builder, but when you only build turbo 4.3-based motors and your clientele includes Tim Allen and Jay Leno, that's really saying something.

In addition to the sheer size of the engine and cam, Jason's 311ci odd-fire V-6 also sports a Precision Turbo & Engine 91.5mm turbo selected by Rockford along with a custom air-to-air intercooler. The chilly charged air is then fed into an Accufab 90mm throttle body and a ported/polished Brodix intake. When mated to Bosch 160 lb/hr injectors, a Weldon billet fuel pump, an MSD ignition, and a F.A.S.T. EFI system, Rockford's brainchild is predicted to achieve about 1,200 hp. Competition Fabrication matched this monster V-6 with a custom set of 1.75-inch equal-length headers and 2.75-inch collectors to spool the turbo. Exhaust exits the turbo via a 5-inch downpipe, which had to be ovaled and sectioned to fit under the chassis before exiting a Borla XR1 muffler.

FB Performance was sourced for a bulletproof 400 in order to match the potent motor. A built-in variable stall control will allow Jason to exceed FB's 9-inch 3,600-stall converter at launch to instead launch at 5000 RPM off the trans brake. A Strange 9-inch rear with 40-spline axles, 4.56 gears, and a spool then transfer that power to the wheels. The final link was the four-link, custom fabricated by Dave at Competition Fabrications, along with a set of removable wheelie bars. The front suspension was also made from scratch along with a custom steering linkage, which utilizes a Strange billet steering rack. Strange double-adjustable coilovers are used in front and back, as are its lightweight brakes and a set of Weld Magnum wheels, which keep unsprung weight to a minimum.

In most race cars, the interior is just an afterthought, but to Jason it was just as important as the rest of the car. Competition adorned the interior with anodized aluminum paneling, a new dash with Auto Meter gauges and carbon-fiber inserts as well as a fabric from Creative Auto. Once all the fabrication was complete, Jason's Syclone was carried over to Gorecki Customs for the straightening and manipulation of the body panels. After Gorecki aligned the factory sheetmetal with the newly fabricated pieces and a Harwood fiberglass hood, the fresh coats of gloss black were applied. Since the chassis and suspension had previously been brought over for matching paint, the last touches were new Syclone decals and an adjustable rear wing.

Not only is Jason's Syclone the baddest of its kind, but it's also one of the cleanest and most unique Pro Street trucks ever conceived. "I always loved that Pro Street look, and not only do I have that now, but I have the only Pro Street truck with a turbo V-6 that I have seen or heard about," said the proud owner. Apparently, that uniqueness caught other people's attention too, as his Syclone took home three awards at the Detroit Autorama car show last year. Once tuning is completed, Jason plans to show the muscle behind this beauty with some 8-second time slips, so V-8s beware.



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