Should I build a turbocharged or normally aspirated Corvair engine?
Normally aspirated (non-turbocharged) engines make more power by generating more air flow at higher RPM. Turbocharged engines make more power through increasing boost at normal RPM. It is generally more expensive to build an engine that will withstand high RPM than to build an engine that can handle more boost. Corvair engines have difficulty breathing because of the restrictive cast intake manifold and small diameter exhaust stacks with a large dent in the side for pushrod tube clearance. A stock “140 HP” engine only made about 110 net HP and 146 ft-lb of torque. In order to get more than about 135 HP, you need to convert the heads to slant exhaust tubes with exhaust headers. To get more than about 170 HP you need to remove the cast intake log manifolds and use two 3 runner manifolds with Weber carburetors or a 6 runner manifold with a 4 barrel carburetor. This is all quite expensive. A set of heads modified by an expert costs at least $3000 plus the intake (another $3000 for Webers a
