22 Here’s the fully assembled “new” Boss 429. It’s taller than the original and wears a few unique parts, but it is essentially an updated version with very similar assembly specs. (The electric water pump seen in the photo was used for dyno testing.) Though this engine produced 670 hp at 6,400 rpm and 556 lb-ft of torque at 5,600 rpm, the builders’ gripe was they simply weren’t able to exploit the engine’s full potential. A roller cam and an extra 100 cubes would push this engine past the 800hp mark, all within a relatively stock-looking package and good driveability traits for a street engine.