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Swapping A Tremec T-56 Into A Road Racing Syclone Can Be Done


Images: StandingMile.com and SyTy.net.

The GMC Syclone [2]is quite possibly the most coveted high-performance pickup truck of all time. Being released in 1991, the compact, S-series based monster literally took the world by surprise with its powerful, turbo V6 engine, 700R4 automatic transmission and all-wheel drive layout. It was even faster than the Ferrari flagship at the time -incredible.

[3]As the years went on, more and more people have taken quite a fondness for the little muscle truck and have taken the level of modifications to new heights thanks to ever-improving technology.

Furthermore, many have even replaced the entire drivetrains of these things with LS power and more modern transmissions, namely the 4L80E.

Now while this gearbox may be more than adequate for typical bolt-on guys running in the 11s and 12s in the quarter with these, Adam of High Performance Trucks doesn’t exactly fit in that category.

Not only is his Sy deep in the 10-second zone with turbocharged V6 power, but it is the most extreme example of a road racing truck we have ever seen. Recently, his GMC smoked the built 4L80E he was packing during the 2nd practice session at the SCCA time trials.

[4]Rather than rebuild the slushbox, the guys at HPT decided on swapping in a Tremec/Rockland Transzilla/Magnum T-56 [5]that also allows the use of the all-wheel drive system and will handle approximately 850 ft. lbs. of torque.

This was as difficult as it sounds judging by the pictures we ran across on SyTy.net, as just about everything included in the build required custom fabrication work, namely; a Corvette transaxle adapter, a custom transfer case adapter, bellhousing adapter, 32-spline billet input and output shafts, along with several custom brackets, including the one that sits under the dash for the Tilton pedal box.

The drivetrain utilizes a McCleod [6] RXT clutch, aluminum flywheel, and fully-adjustable throw out bearing assembly.

We could go on and on about this truck as this is probably one of the top five heavily modified Syclones in the world. But that goes beyond the scope of this article. If you want to learn more about the HPT Syclone, jump over to SyTy.net [7], or HighPerformanceTrucks.com [8]and prepare to be awestruck.