More stories related to 2005 Greater L.A. Auto Show They are not switching from front-wheel to rear-wheel drive – as Chrysler Group did with its large cars – but the Chevrolet Impala and Monte Carlo are undergoing significant changes for the ’06 model year, including dropping General Motors Corp.’s decades-old 3.8L OHV V-6 engine.

Unveiled at the 2005 Greater L.A. Auto Show, the ’06 Impala and Monte Carlo feature all-new 3.5L and 3.9L OHV V-6s, the return of the small-block V-8 with the LS4 5.3L (equipped with fuel-saving Displacement on Demand technology) in the SS performance versions, a new look inside and out, retuned suspensions with a wider track, a new family of wheels and tires, enhanced antilock brakes (except on the base model) and traction control.

“The ’06 Impala and Monte Carlo deliver more of what customers want from a large sedan or coupe – uncompromising roominess, but with the performance and styling of a sports car,” says Chevrolet General Manager Brent Dewar.

Both vehicles hold distinctive positions in the market. Impala, met with skepticism when it debuted in 1999, is an unqualified success, with sales topping 1 million units over five years. The Monte Carlo remains one of the industry’s only midsize coupes.

’06 Chevy Impala

’06 Chevy Monte Carlo

But the vehicles, both built at GM’s Oshawa, Ont., Canada, assembly plant, are aging and about three years away from switching to an all-new platform (likely RWD).

The new OHV V-6 engines, which feature cam phasing to optimize performance and economy, is standard in both vehicles, with the base models receiving the 3.5L variant that produces 210 hp. Up-level models are available with a 240-hp 3.9L.

The 303-hp 5.3L V-8 in the Impala SS and Monte Carlo SS switches between 8-cyl. and 4-cyl. operation – providing up to 12% improved fuel economy, GM claims.

All engines are combined with an electronically controlled 4-speed automatic transmission.

The front-end structure is more robust via stronger ties between the upper and lower frame rails, and the extruded aluminum engine cradle’s lateral stiffness is increased with a new, 1-piece machined rear crossmember and new aluminum rear body mounts.

Both vehicles feature McPherson strut coil-over-spring independent front suspensions with gas-charged 4-valve struts and a stabilizer bar. Taller jounce bumpers in the front suspension help enhance stability and control, GM says. The rear suspension uses a trailing arm, tri-link setup with gas-charged, 4-valve struts and coil springs. A rear stabilizer bar is standard on all models.

Interior and exterior design alterations arguably are more beneficial for the Impala than Monte Carlo.

Impala’s cabin is dressed with a classy emblem of the African antelope on the instrument panel, which is moved forward 4 ins. (10.2 cm). The A-pillar also is moved forward 2 ins. (5.1 cm) – modernizing the outgoing car’s dated appearance and increasing interior space.

Impala and Monte Carlo also feature fatter stereo and climate controls knobs. “Bigger knobs are where home stereos are going, and so we’ve adopted that here,” says Lewis Cole, Impala/Monte Carlo vehicle line director.

Impala’s forward-flip rear seat cushions create a covered storage area beneath the seat. The seat back also folds flat to create a pass-through from the trunk– an exclusive feature in the midsize segment, GM claims.

The up-level, Nuance leather-covered seating features French seams on the center cushions and increased lumbar support. Impala models, except the SS, offer a wood-trimmed appearance or a brushed sterling-appearance trim. The Impala SS comes standard with a techno-pattern trim panel.

Both the Impala and Monte Carlo offer an MP3/CD-radio with a 2-line, 32-character reconfigurable display depicted in soft blue lighting.

The Monte Carlo features a revamped cockpit-style instrument panel with a new layout and control center stack. A sportier shifter with chrome accents also is added.

Neither the Impala nor Monte Carlo undergo radical exterior styling changes.

Monte Carlo’s new design cues reduce its overall length by 1.2 ins. (3 cm) compared with the ’05 model. All the Monte Carlo models feature a rear decklid spoiler.

The ’06 Impala discards its predecessor’s unpopular rear end for split taillamps. Both SS models are dressed with front-end appearances separate from the other models, including dual-split grilles that have a black-diamond crosshatch pattern.

bcorbett@primediabusiness.com