Toyota Tundra 4x4

Tundra's new iForce V-8 is a thing of mechanical beauty.

After muscling into the full-stature segment two years ago, the Toyota Tundra now brings an all-new 4.6-liter V-8 engine to the towing party. To check out Toyota's newest powerplant, I hitched up my 19-foot Glastron and mapped a tow-test route across lower Michigan. First observations: This is one smooth engine with a butlersilent disposition and ample lickety-split at the hot end of the gas pedal.

Tundra's new iForce V-8 is a thing of mechanical beauty, with mostly aluminum construction and dual-overhead camshafts providing variable intake and exhaust-valve timing. About the only technical tidbit it lacks is direct fuel injection. With 310 hp on tap, this engine never broke a sweat hauling my 3,540-pound boat and trailer. Standard with the part-time 4x4 driveline ($3,050 extra), the new 4.6-liter V-8 wriggles in between Tundra's 4.0-liter V-6 and 5.7-liter V-8, and is mated to an electronically controlled six-speed automatic transmission. A handy toggle on the column shifter delivers expeditious gear changes, taking the strain out of grades.

Even with the boat in tow, I found the new Tundra quick on its feet. It demonstrated a smooth ride and excellent sense of direction while cruising at the legal limit. Gear changes were barely noticeable. Powerful brakes provided multiple straight stops in less than 200 feet from 60 mph with the trailer attached. The turn circle is a tidy 44 feet - not bad for a big truck with four doors, a roomy back seat and a 6-foot-6-inch bed.

The best surprise was the gas mileage I recorded. While my payload was less than half the Tundra's 8,300-pound towing capacity, the 14 miles it delivered per gallon of regular fuel was an impressive 6 mpg better than the 381 hp 5.7-liter Tundra tested two years ago. (That truck was pulling 5,200 pounds.)