For 1970 vertical grille inserts replaced the horizontal bars of the 1969, and "Grand Prix" nameplates were moved from the lower fenders to the rear C-pillars. The vertical chromed louvers from the C-pillars were moved down to the lower fenders. The optional 428 CID V8  was replaced by a new 370 HP 455 CID V8 with 500 ft. lbs of torque. The base 350 hp 400 CID V8 was still standard, but a low-compression 400 CID engine was available with a two-barrel carburetor. Automatic transmission was offered as a no cost option.

Interior trim received minor revisions, and a bench seat with center armrest returned as a no-cost option vs. the standard Strato bucket seats and console. Bench seat-equipped Grand Prixs got a steering column-mounted shifter with the automatic transmission along with a dashboard-mounted glove box. Power front disc brakes became standard equipment.

Due to the success of the 1969 Grand Prix, other GM divisions followed suit and introduced similar cars for 1970. The Chevrolet Monte Carlo used the same basic A-body-Special as the GP but with a two-inch shorter wheelbase and Oldsmobile decided to further capitalize on strong sales of its intermediate Cutlass line by introducing a new Cutlass Supreme coupe with a formal roofline similar to the GPs but on the standard 112" wheelbase used for two-door A-body intermediates.

Production:

The introduction of the Monte Carlo and Cutlass Supreme cut into the Grand Prix's sales dominance, and as such, GP sales  dropped to 65,750 in 1970.

Available Engines:

• The 350 HP 400 CID four-barrel V8 remained the standard engine.
• A 265 HP 400 CID two-barrel was the step-down optional engine
• A 455 CID V8 with four-barrel rated at 370 HP