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  The first 4.3L Chevrolet engine appeared in 1955 in the Chevrolet Corvette. The first Chevrolet small block engine, it produced around 162 to 180 hp. Since then several 4.3L engines General Motors developed came out on Chevy vehicles that ranged from full size cars to pickup trucks. There are several differences between versions of the 4.3L engines, all of them sporting a wide range of horsepower and torque output. The more notable 4.3L engines Chevy produced include the 265, the 262 and the Vortec 4300.
  
  

265 Small Block Engine

• The first 4.3L V8 Chevy engine was built out of necessity for the Corvette. During 1956, the Corvette was suffering from low sales because of its low performing 235 engine. Chevy designed the 265 in order to equip the Corvette with a more powerful powertrain. It came with either a two-barrel or a four-barrel carburetor. The two-barrel variant was able to produce an output of 162 hp 4,400 rpm and a torque of 257 foot-pounds at 2,200 rpm. The four-barrel variant was able to produce 180 hp at 4,600 rpm and its torque was 260 foot-pounds at 2,800 rpm.
  
  

262 Big Block

• In 1975 Chevy introduced another 4.3L engine, this time in the body of the 262 Big Block V8 engine. The 1975 Chevy Nova had this engine, and it was able to produce 110 hp at 3,600 rpm. It had hydraulic valve lifters along with an Overhead Valvetrain (OHV) configuration. This engine block was cast iron, and had a two-barrel carburetor.
  
  

Vortec 4300

• The Vortec 4300 was another 4.3L engine that Chevy introduced in 1985. Also labeled as the "LB4," it was different from the previous 4.3L engines since had a V-6 configuration. It was also based on the larger 5.7L V-8 engine, with two cylinders removed. This engine had a cast-iron engine head and cylinder block and was in major Chevrolet vehicles, including their popular line of C/K pick-up trucks. On a 2005 Silverado, this engine had a gross output of 195 hp at 4,600 rpm and a torque output of 260 foot-pounds at 2,800 rpm. It still used the same OHV configuration with 12 valves.