For this final round, the stakes were raised: A 6.0-liter-powered GM with a towing package is the most direct comparison to the Tundra with the 5.7, and we added weight in two forms. Ding, ding! Cue the ring-card girls.

GM's latest 6.0-liter adds active fuel management and variable valve timing to its single-cam pushrod aluminum block. It's rated at 367 horsepower at 5500 rpm and 375 pound-feet at 4300 rpm, just 14 and 26, respectively, shy of the Tundra. The Toyota also has the wider powerband on paper with 2000 rpm between peaks as opposed to the 6.0-liter's 1200 rpm.

Margins like that seem almost insignificant and might be with equal gearing. However, gearing isn't equal, with Tundra's 4.30:1 axle ratio besting GM's shortest-available 4.10:1, and the disparity in gear choices. Combine the Toyota's higher output with deeper gears, and it puts nearly 20 percent more twist to the wheels in first gear and the gap widens from there (see sidebar, "The Gear Box"). With $23,000 cars and SUVs sporting six-speed automatics, the General can't get them in $35,000 pickups soon enough.

Those advantages translate to enough extra grunt that the Tundra accelerated an average of 18 percent quicker in our battery of towing tests, which included grades, 0-to-65, 45-to-65, and 20-to-65 mph, the last because even when towing a heavy load, the Tundra's engine spun the tires to invoke traction control at starts. And with more gear choices to optimize efficiency, the Tundra averaged 15 percent better fuel economy in the process. We watched the readouts carefully and didn't see the GMC's V-4 mode display very often, noting it primarily at drop throttle. In EPA rankings, the GMC rates 1.0 mpg better, numbers our real-world exercises (towing, hauling, highway, city) didn't agree with.

At the building supply center, we forked more than a ton of cement bags into the Tundra and drove the truck over to the GMC (which was parked away from the loading dock), where half the cement was offloaded into the Sierra's bed. Despite being roughly 850 pounds beyond weight limits, the Tundra still had some compression travel left in the rear leafs. Loads matched, we hit the road, experiencing surfaces that were good, marginal, and bad.

Everything we liked about the GM from Round 2 was here: Comfortable seats, simple, clean dash design, nicely weighted precise steering with good feedback, and a ride that was well controlled, partly because it was still about 600 pounds below GVWR. Whoop-de-doos didn't get it airborne. It has stiffer spring rates and a lower profile than the Tundra, which kept it flatter. Also, at least one pilot preferred the Z85/NHT "handling/MAX trailering" suspension to the Z60 setup used in the previous round. Testers noted the GMC felt more controlled when running quickly down the winding roads, which is attributed to the firmer suspension, lower ride height (and probably lower center of gravity), and the perceived security from higher window sills. It's worth mentioning that because of an aluminum block, disc brakes, and smaller wheels, this 6.0-liter VortecMAX truck weighs 159 pounds less than a cast-iron 5.3-liter/Z60 with drum brakes and 20-inch wheels.

Naturally, there were a few exceptions. The more truck and trail-appropriate Wranglers made the GMC cabin the noisier of the two, and the 6.0-liter's rear discs gave better feel and welcome added fade resistance charging down eight- to 12-percent hills. Last and least important, the interior lacks the same warmth and flair in black that it does in lighter hues. In general, the GMC's controls are more solid and more communicative than the Tundra's, becoming a distraction only during maneuvering as we outpaced the Sierra's steering pump twice.

Related Articles:

Round 1: Here's what we know

Round 2: Down and Dirty

On the other hand, the Tundra was loaded to GVWR. Here, you can get the off-road suspension and towing packages together, and its Bilsteins proved their worth as every inch of suspension travel--and in at least one instance, about an inch of the bumpstops--got used. There were never any control issues, nor did stability electronics get called on to save the day, but the GMC's obvious payload advantage made it an easier drive. The light steering that turns tighter is welcome in urban and backing situations, but the touchy gas pedal led to a lot of tire-scratching, despite its long travel and smoother modulation at speed. The Tundra's brakes are no less bulletproof than the GMC's, but were used less, since the console-shifted six-speed gave more opportunities for compression braking; we wish it didn't default to fourth when going to Sport (or manual) mode, as fifth was often just right.

For hauling, the GMC offers two significant advantages--cargo capacity that's more than 600 pounds above the Toyota's and a lower bed to lift heavy loads into. Once unloaded, we also found the GMC's ultimate axle articulation equaled that of the Z60's, despite the extra 400 pounds of ability above the Z60, and the Tundra's invasive traction control needs to be dialed back a bit--it was impossible to spin the tires to clear mud (after four truck lengths on pavement at full throttle, we were up to a whopping 14 mph).

We then arranged heavier loads and much more aero drag in the form of 27-foot toy boxes (see sidebar, "Life in RedLine") from Fleetwood. Without weight bars on, these trailers dropped the hitch on the Toyota 4.2 inches and the GMC 4.0--between this and the Tundra not being on bumpstops at twice its rated load, maybe Toyota is sandbagging on payload numbers or just likes bigger reserves for cooling and braking systems.

Once the trailer was hooked up, the GMC's comfort factor went away for one simple reason: The VortecMAX NHT trailering package doesn't include a mirror upgrade. Since you can see only what's next to you but not what's behind, you're forced to drive it like an old tail-dragger airplane, weaving to check the rear view in alternate mirrors. For a truck that essentially duplicates the old "light-duty" 3/4-tons, its trailer package needs to be bumped up a C-note or two, adding extension mirrors to the NHT trailer package.

Neither truck had any significant issues towing. Once it was warmed up, the Tundra's lethargic ATF temperature indicator never wavered, while the GMC (with gauges that all moved regularly) registered a high of 199 degrees Fahrenheit on its digital display during acceleration testing. During our test, we remained well below maximum GCWR for both trucks and the weather was cool, so if you're pulling max load in the heat, keep an eye on it.

As we tested, the trailer drove the back of the Toyota in turns. The toy box had more effect on the front of the GMC, with no tendency for the tongue weight to push the truck, but did require more frequent minor steering corrections. Directional stability in the GMC was slightly behind that of the Toyota, yet close enough that it could be traced to tires and should be easy to adjust out with weight-bar preload. In tow/haul mode, both trucks switch that function off with the ignition (you'll have to turn it back on at every gas and food stop). By the end of the test, both had that "hamster-in-the-back-seat" squeak, and after a few hard trips down a bumpy road, the GMC needed a harder spring on its fuel door as it popped open three turns out of seven.

After Round 2, Toyota announced Tundra pricing, and with a $38,550 base for our Limited Double Cab 4WD (D.C. 4WD V-8s start around $30,000) it's a bit higher than the segment average but fully competitive. That price includes the big V-8 and six-speed automatic, tailgate assist, stability control, and towing package, most of which are optional on the Sierra. As similarly equipped as possible, the Sierra has a price lead of about $900; however, the Sierra doesn't offer a six-speed auto (yet) or other Tundra standards like front side airbags and brake assist.

With the GMC equipped for family recreation as tested, its price advantage of a few hundred dollars, more appealing interior package, and greater payload capacity aren't enough to overcome the Tundra's superior powertrain performance, safety equipment, larger cabin, and better fuel economy in every situation. The third time is indeed the charm for Toyota, as this third-generation full-size pickup has set the benchmark another notch higher.

Life in RedLine
The 27-foot RedLine 230FSE stickers at 5505 pounds empty with 806 on the hitch, and has a GVWR of 9995 to stay under the license endorsement limit found in some states. Since that pin weight translates to about 1100 pounds added to the rear axle, we hooked them both with identical weight-distributing hitches, each with three links on the bars.

They appear more nose-down than we'd normally tow for three reasons. One, the trailer jack wouldn't go any higher for loading (we recommend carrying wood blocks). Two, the majority of the payload weight will go behind the trailer axles. And three, the nose-heavy weight helped the trucks find traction under power and helped them use the rear brakes more--we skidded the rear axle on one trailer about three feet because of the forward-tilt attitude, and that only happened once.

Our Sierra didn't offer a simple plug-and-play setup for brake controllers, requiring the installers to make direct wiring connections. The Tundra was delivered with a controller already installed, but tow-package (and all V-8) Tundras come with a plug-in connection at the end of the brake-controller harness.--GRW

The Gear Box - GMC Sierra/Toyota Tundra
GEAR1st2nd3rd4th5th6thReverseCrawl
Gear ratio3.06:1/ 3.33:11.63:1/ 1.96:11.00:1/ 1.35:10.71:1/ 1.00:1NA/ 0.73:1NA/ 0.59:12.29:1/ 3.06:13.06:1/ 3.33:1
Overall ratio12.55:1/ 14.32:16.68:1/ 8.43:14.10:1/ 5.81:12.87:1/ 4.30:1NA/ 3.14:1NA/ 2.54:19.39:1/ 13.16:134.0:1/ 37.5:1
Pwr to axle @ peak lb-ft4705/ 57422505/ 33801537/ 23301076/ 1724NA/ 1259NA/ 1019 3521/ 527712,750/ 15,037

 2007 GMC Sierra SLT 1500 Ext Cab 4WD2007 Toyota Tundra Double Cab Ltd 4WD
General
Engine90° 6.0-liter V-8, alum block/heads 90° 5.7-liter V-8, alum block/heads
As tested curb weight, lb5393 5620
As tested payload capacity, lb1807 1180
GVWR, lb7200 6800
GCWR, lb16,000 16,000
Towing capacity, lb*10,453 10,226
Performance
Acceleration, 0-65 (towing), sec25.7 21.6
EPA fuel economy, city/hwy 15/19 14/18
Fuel economy, towing7.20 8.55
Price
Base price$34,250$38,550
Price as tested$40,760$41,055
* as tested, with 154-pound driver

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