2006 Chevrolet Impala

Yeah, we know: The Chevrolet Impala barely shows up on your radar screen, except maybe when that Impala is attached to the local constabulary's radar gun or greets you at an airport rental-car lot. But it's impossible to ignore that it's the best-selling American-branded car, beat out in 2004 only by the Toyota Camry and Honda Accord. Sure, a goodly percentage of those were lower-margin fleet sales, and many were accomplished via massive rebates, but the fact that Chevy managed to move 290,259 Impalas last year--no matter how it managed it--suggests cash-cow status for a company currently running a thin herd.

For 2006, Chevrolet says we're getting an "all-new" Impala. Sure, the nose and tail look different, but the profile hasn't changed much. But looks don't tell the story: Only about 25 percent of the 2006 Impala is holdover, and that means lots of new bits and pieces.

One new bit is welcome: a 303-horse version of the 5.3-liter V-8 for the SS model, the first Impala V-8 since 1996. And, yes, devotees of that particular Caprice-based Impala SS might complain the powered wheels are on the wrong end, but we'll take power where we find it, front drive or not.

The V-8 is one of three engines offered in the 2006 Impala. The base model has a new 3.5-liter, 211-horse V-6, replacing the weak-willed, 180-horse, 3.4-liter V-6 standard for 2005. The new mid-level engine is a 3.9-liter V-6 with 242 horses, replacing last year's 200-horse 3.8-liter V-6; it even has two more horses than the supercharged 3.8 in the 2005 Impala SS. Incidentally, this engine lineup is identical for the 2006 Monte Carlo, which follows the Impala by about three months.

Both V-6s and the V-8 share the familiar 4T65-E four-speed automatic, with beefed-up internals for the V-8. Yes, a five-speed automatic was considered, but budget concerns and the reliability of the 4T65-E earned it the nod. And while another gear or two would be nice, all three powerplants have enough torque to make the four-speed acceptable, if hardly cutting edge.

The 3.5- and 3.9-liter V-6s share only valve lifters with previous GM engines. More than 80 percent of the parts are -common for the two V-6s, however. Both have a rudimentary version of variable valve timing--there's a vane-type camshaft phaser that changes the angular orientation of the cam, thereby adjusting the timing of the intake and exhaust valves.