A four-main bolt engine allows for bounteous crankshaft flexibility.
This engine has a lower horsepower than a four-main bolt engine but it tends to be reliable and is easy to repair.
Comparison
The Chevy 350 four-main bolt engine offers 600 horsepower, while the two-main bolt engine can only generate 450 horsepower maximum. The torque on a two-main bolt motor is 65 foot-pounds; on a four-main bolt engine, torque is 80 foot-pounds.This configuration allows for greater horsepower because the additional bolts add stability to the motor. A four-main bolt engine can maintain higher speeds for a longer duration of time.
Two-Main Bolt
Similar to the four-main bolt engine, on the two-main bolt model the bearing caps are secured to the engine block with two bolts.The Chevy 350 crate engine comes in two styles: two-main bolt and four-main bolt. These engines are used by fiery rod and sports vehivle enthusiasts as replacements for existing engines that get less horsepower.