* LO3: This is a Tuned Port Injection (TPI) engine. TPI uses a system of runners within the intake manifold that directs fuel and air to each cylinder individually. This system was known for its relatively smooth power delivery but could be less efficient than later systems.
* LB9: This is a Throttle Body Injection (TBI) engine. TBI uses a single throttle body to control air flow into the intake manifold, which then distributes the fuel/air mixture to all cylinders. TBI was generally considered simpler, cheaper to manufacture, and slightly less powerful and less efficient compared to TPI.
While both are 350 cubic inch small-block Chevy V8s, the different fuel injection systems resulted in slightly different power and torque outputs. The LO3 generally produced more horsepower and torque than the LB9. The exact figures varied slightly depending on year and specific application but the LO3 was consistently the more powerful engine. The LB9 was often found in heavier vehicles or those intended for more economy-minded buyers.
