Small Blocks

• The smallest V8 available in the 1970 Chevelle was the 307-cubic-inch version. Although not as popular a replacement engine as the 350, a 307 matching the original specs can be ordered by Chevelle owners intent on restoring their vehicles to original condition. The crate engine can develop up to 200 horsepower and exceeds the original 307 performance. Crate engine builders test the engine for compression, oil pressure and leaks.
  
  

The 350

• The highest selling Chevy crate engine is the 350, which was an optional V8 for the original 1970 Chevelle. The 350 crate engine comes in a horsepower ratings ranging from 270 to 450 horsepower. The high-performance versions generate 425 and 440 horsepower, while milder versions average about 290 horsepower to take regular 87-octane gasoline.
  
  

Big Blocks

• When the 1970 Chevelle debuted, the 396-cubic-inch V8 was enlarged to 402 cubic inches. Still dubbed the 396, the crate engine develops up to 375 horsepower and features a steel crank, General Motors rods and oval ports and forged pistons. The largest V8, the 454 crate engine, features the original specs, but runs on today's fuels without being damaged.