International SyTy Registry

GMC Syclone, Typhoon, & Sonoma GT History and Data

SyTySoGT Prototypes & Concepts

  • Bench Seat
  • Column Shift
  • Manual Roll-up Windows
  • Forrest Green/Light Gray Cloth
  • No Cladding
  • Production Syclone Wheels with Corvette Center Caps
  • Privately owned by David Kress, located in Pennsylvania



ImageConcept Syclone #1. Chicago Autoshow debut (1989)

ImageConcept Syclone #2. Detroit Autoshow debut (1989)

ImageBuick Syclone. Privately owned.

ImageCodename “Lil’ Red Truck”.  During the Syclone’s development, there was a debate to introduce it as a S10 version. Chevy wanted it while GMC refused it….after all, they were in charge of the concept and platform. Before the idea was completely squashed, the development team threw together this 1989 S15 complete with custom 16″ steel wheels with correct offsets to accommodate the Safari AWD driveline and installed a full-on Syclone drivetrain. The truck had a bench seat, manual windows, an a column shift. The last known whereabouts of this truck was in Virginia in 1999 with around 222k on it!

ImageChuck Mountain’s Personal Truck. 3.8 liter engine and special hard tonneau cover custom made by Leer Corp. Stolen, recovered and then scrapped in 1992. Proto #001 One of the 5 that survived. Maroon colored.ImageCodename “Old #9”. Sierra Classic S-10 Solid Grey with no cladding. Naturally Aspirated 4.3 liter centerport engine with Column Shifter. AWD with Syclone Rims. Proto #009

ImagePrototype #015 Syclone. Engineering Truck. The truck has PAS 001 on the side windows and the front of the rear-view mirror. Interior:

    [*]Console is yellow, made out of a prototyping plastic. [*]It does have the Syclone seats. But that is the only place (except for the intake) that it says Syclone. [*]The interior carpeting is still the 4×4 carpet, with the hole in the carpet for the 4×4 shifter. [*]It does not have the Sunbird Turbo dash, instead it has some other pontiac dash. [*]It has a turbo gauge, tach, 140mph speedo, and all the other things.
    [*]The engine is basically that of a stock Syclone, with a few exceptions. [*]The cam is slightly larger, the pistons are from a turbo 350, and the Turbo is a garret, instead of mitsu. [*]The intercooler is all custom, built by garret. [*]The ECM sits in the glove box, and is entirely custom.
      [*]It can be reprogrammed on the fly, using a laptop computer. [*]The chip stores “defaults” and can be replaced.
    [/list] The engine has been modified from PAS from it’s original form. It is believed that the intake, turbo, and intercooler have been replaced with semi-‘stock’ parts. The originals are in Marty’s hands, or so we think. Exterior:
      [*]The vehicle does not have any ground effects and has S-15 steel bumpers. [*]There is a est 350lb weight welded to the rear bumper to keep the rear end down while pulling a Towing Dyno. [*]In the bed of the truck there is a gas cooler box. This cools the gas using NOS.
      [*]The transfer case came out of the AWD Astro Van, the Front prop shaft was developed at GKN in Auburn Hills, Michigan. [*]The front differential is not that of a bravada, it is a normal 4×4 diff, that has had the shift mechanisms removed.
    We believe this truck was donated to a church group, which then raffled the truck off.

    ImageUnknown Syclone. Wrecked in testing.

    ImageProto #010. Totaled into a wall on 696 Highway.

    ImageJim Stokes’ baby. Was to be ready every week for Magazine testing. Fiberglass air duct. Fiberglass Cladding. Proto #019. Became the PPG pace truck that GM still owns.

    ImagePre-production Syclone. Owned by Mike Poccobello. Used on horse farm as a work truck. Production appearance. Sold privately in 2002. Proto #018 – “Queen Vehicle”

    ImagePre-production Syclone. Production appearance. 1992 style mirrors. Sold privately in 2002.ImageCodename Queen Bee. #1 Full Production Syclone, Charcoal with Black Cladding. Used in all Dimensional work, Suspension work/testing and to fit all prototype parts. Never Left the Block, only driven around GM grounds.


    Image92 Pre-Production Syclone. 30,000+ miles. Sportmachines Video Truck. Privately owned. Located in TN. Currently for sale

    Image92 Pre-Production Syclone. Brochure Truck. Privately owned. Located in SC.

    ImageFirst Production 1992 Syclone Vin #0001. Purchased by Maldaver when PAS closed. Currently located in NY. Never Registered.
    Located in a Junk Yard in NY.
    Bought by Maldaver when PAS closed.
    No VIN # stamped on the frame.
    It was bought from Maldaver (now closed) for $600.00
    Now it just sits to rot.


    ImageConcept Typhoon. The name “Typhoon” hadn’t even been authored at the time of this drawing, so “Syclone” was used.

    ImageTyphoon Clay Model. All the fascias and cladding were made of clay. The front turn signals and fog/driving lamps were made from paper and just colored or rendered to appear real. Rear Spoiler and 1991 Syclone mirrors.

    Image1991 Prototype Typhoon “Shamu”

    Image1991 Prototype Typhoon. No cladding, Jimmy interior.

    ImageJimmy Z-34. Full 1993 Typhoon interior. No cladding. Dubbed the ’94 prototype.ImageAll Prototype 4 door Typhoons

    ImageChevy Typhoon. Full typhoon pkg, with Corvette center caps. Used to market test the Typhoon pkg in Europe where GMC had no license at this time.

    ImageGMC Sonoma GTX Prototype

    Image92 GMC Sonoma GT Extended Cab 4×4. Only one ever built, also only Sonoma GT which is 4×4, Built ’93 Production year. Owned/Driven by GMC executive.