1955 Chevrolet Bel Air 150210 on 2040-cars

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Chevy's 6.6-liter Duramax is pretty much all new

To say there's a heated battle in heavy-duty pickups is an understatement, with Chevrolet, Ford, and Ram constantly trading blows of increased torque, horsepower, and towing capacity. The latest salvo is the revised, more powerful turbo diesel 6.6-liter Duramax V8 in the 2017 Chevy Silverado. It has 910 pound-feet of torque, an increase of 145, putting it nearly level with the Ford Super Duty. Here's a closer look at where those gains come from. How exactly did Chevrolet add all that torque plus 48 horsepower? The automaker essentially took a fine-tooth comb to the entire engine. Chevy says it changed 90 percent of the V8, and the cumulative effect of those small changes adds up to big increases. As you might guess, the turbocharger is updated. The larger unit features electric actuation of the variable nozzle turbine (VNT), and what Chevy calls a double axle cartridge mechanism that separates the VNT moving parts from the housing. That helps with heat performance as well, with a claim that the exhaust side of the turbo can run continuously up to 1,436 degrees Fahrenheit. Helping that cause are six exhaust gaskets made of Inconel - an nickel alloy that contains chromium and iron – and upgraded stainless steel for the exhaust manifold. Despite having the same cast iron cylinder block, albeit with some minor enhancements, the engine has new cylinder heads, pistons, piston pins, connecting rods, and crankshaft, which have all been upgraded to handle 20 percent higher cylinder pressures. Alongside the increase in pressure, Chevrolet also increased the cylinder head's structure with a honeycomb design. The pattern features high-strength aluminum with dual layer water jackets that not only improve strength, but also optimize water flow for better cooling. For 2017, the cylinder head also benefits from integrated plenum that aids the engine in getting more air under heavy loads. The cylinder head isn't the only component to get a minor update, as the pistons have a larger diameter pin for improved oil flow. The same detailed improvements has been bestowed to the humble connecting rods (second in our hearts only to the inanimate carbon rod). The new design has the bolts oriented roughly 45-degrees to the rod instead of parallel. The angle split design, as it's called allows for easier passage through the cylinder.

MotorWeek looks back at 1995 Chevy Tahoe, GMC Yukon

MotorWeek's Retro Review series gives us a nostalgic look back at some of the best sports cars and luxury sedans available in the 1980s and '90s. For its latest clip, the show shifts gears to remember the 1995 Chevrolet Tahoe and GMC Yukon. Similar to the success of crossovers today, SUVs were tallying big sales and making big money for automakers in the mid-'90s. The Tahoe and Yukon filled slots in the market as steps down from the larger Suburban. These twins weren't wanting for space, though, with plenty of room to haul around a family. MotorWeek came away generally impressed too, and called the models some "of the better riding sport utilities we've ever experienced." This review comes with some jazzy, electric guitar licks to enjoy in the background.

Helicopter crashes on Top Gear Korea set while chasing Corvette ZR1

The formula of Top Gear Korea is seemingly about the same as it is everywhere else in the world, including the flagship British original: involve interesting cars in fantastical situations with charismatic hosts. That prescription has proved to be pretty reliable over the years, and has lead to some truly memorable and exciting pieces of television.
Something like that was undoubtedly what the Korean producers were after when they lined up this segment - a drag race between a Chevrolet Corvette ZR1 and an AH1 Cobra military helicopter. The planners almost certainly did not expect the filming of the segment to go quite as wrong as it actually did, with the helicopter actually crashing into the dirt after the "drag race" had been completed. Thankfully, we're told that no one was seriously injured in the crash, but the footage, in the video below, is pretty damn chilling to watch, nevertheless.