Project Truck Norris Gets a Big-Block and T56

For the last couple years, we’ve been driving Truck Norris around with a 383 small-block Chevy under the hood and its original four-speed transmission. While that was fun, it’s time to get serious if Truck Norris is going to pay tribute to the karate-chopping badass it’s named after. Coincidentally, we’ve been working with AEM Performance Electronics on an EFI system on our BluePrint Engines 540 big-block. Impressed with the dyno-chassis results, we decided to drop that big-block into the C10’s engine bay. A move we’re certain Chuck would approve of. Making 716 hp and 680 lb-ft of torque, our big-block demands a transmission upgrade. While the C10’s stock SM420 four-speed is probably a worthy candidate to live behind a big-block, it’s first and foremost a truck transmission. This trans is tough as nails and probably could crush rocks, but its gearing just isn’t suited to the type of driving we will be doing with our 1967 C10. The SM420’s 7.00:1 First gear was designed specifically to provide low-powered inline-sixes and small V8s extra mechanical leverage needed to get the truck moving when hauling a bed full of stuff. Other than that, it’s not used in everyday driving. Even the 3.60:1 Second gear is virtually useless with a potent small-block making anything approaching 400 lb-ft of torque. Second gear, plus the truck’s 3.73:1 axle ratio, works out to a 13.42:1 final drive. Combine that with a 27-inch-tall rear tire, and from a standing start, you have to shift gears halfway through the intersection because the engine speed is racing past 4,000 rpm, yet you’re only traveling about 20 mph. In short, the SM420 is a great transmission for a truck with a little engine, but it’s not suited for any sort of performance application, nor was it ever intended to be. TREMEC’s T56 Magnum is a performance transmission, however. It’s the aftermarket version of the TR-6060, the very capable gearbox found under such notables as the Hellcat Challenger, Z28 Camaro, and ZR1 Corvette, to name a few. The Magnum is rated to 700 lb-ft of torque, and our sources inside TREMEC say this is a conservative figure. We’re confident it will live behind our big-block, although higher-rated versions of this transmission available from American Powertrain should you be making more power than we are. The Magnum differs from previous versions of the T56 most notably because of its wider gears, which offer increased surface area of tooth contact between the gears in the main- and countershafts. This means the Magnum will withstand higher torque levels than the previous versions found in C4 Corvettes, early Vipers, and fourth-gen F-cars. American Powertrain provided the T56 Magnum, along with its installation kit, which includes an aluminum-transmission crossmember, hydraulic throw-out bearing, a flywheel and clutch kit, speedometer cable, and a cool shifter and cue-ball shift knob. The T56 Magnum is a very versatile transmission for aftermarket applications because the shifter can be placed in any of three different locations on the top of the transmission case. For the 1963–1972 C10s, American Powertrain mounts the shifter in the forward-most position so the shifter handle’s throws will clear the factory bench seat in all gears. Our C10 was also blessed with the benefit of having the “high-hump” floor. The transmission hump actually bolts to the floorpan; it’s an access panel to the transmission. The hump is taller than the transmission tunnel would be in a rear-drive C10 with automatic transmission, and the tall bits of the T56 fit this space perfectly. It’s as if these things were designed to have T56s installed someday! - See more at: http://www.whyps.com/News/Hydraulic-industry-articles/project-truck-norris-gets/52289#sthash.LPFK7hRv.dpuf