paint. For the 1990 model year, all Blazers now had a standard rear wheel anti-lock braking system. A new electronic speedometer system, with a 6 digit odometer on the dashboard was also introduced for 1990, along with non-asbestos brake linings. A new brake warning light on the dashboard was also introduced for 1990. The Blazer body also used double sided, galvanized exterior sheet metal. A new option for 1990 was power mirrors. 3 point shoulder harness also become standard for rear passengers. The rear seat arm rest were eliminated from rear seat to make room for shoulder belts and pads were added to the wheel housings. For 1991, two new exterior colors, Brilliant Blue and Slate Metallic were offered. Drivetrain The K5 Blazer was fitted with a inline-six as standard through 1984. Available engines included a inline-six, small-block V8s of 305, 307, 350, or 400 cubic inches (5.0, 5.0, 5.7, and 6.6 liters), and a 6.2 L Detroit Diesel V8. The six-cylinder Blazer was not recommended for towing. Since 1981 (in the wake of the 1973 Arab Oil Embargo and the 1979 energy crisis), Chevrolet and GMC used the smaller displacement 305s with a 9.2:1 compression ratio. These engines produced nearly as much torque as the 350, giving a similar driving feel. However, these power plants were underpowered and prone to detonation (engine knocking), especially with the electronic spark control module. To achieve the 9.2:1 compression ratio, the cylinder head chambers were smaller, measuring 56 cc instead of 76 cc. After 1987, when throttle-body injection was introduced in the truck engines, the 350 was made the standard power plant. Corporate 10-bolt axles were upgraded to 30 spline axle shafts from previous 28 spline shafts in 1989. In addition, the standard L05 5.7-liter V-8 now had one serpentine accessory drive belt in place of the older multi-belt accessory drive setup. 1989 was the first year for the NP241 transfer case and also the only year for speedometer cable driven version of the NP241. The 5.7 liter V8 (L05) engine was improved for 1990 with the addition of improved oil control rings, a redesigned rear crankshaft seal, a new camshaft sprocket design, non-asbestos intake manifold gaskets, and heavy-duty intake valves. For 1991, the 700R4 was renamed to the 4L60. The TBI (throttle body injection) system used on the Blazer's standard 5.7 liter V8 had longer throttle shaft bearings, new throttle return springs,