Testing Compression
- Disconnect the BAT terminal from the High Energy Ignition (HEI) distributor or module. Check compression pressure with engine at normal operating temperature, all spark plugs removed and throttle valve wide open.
- Insert a recording-type compression gauge, and crank each cylinder through 4 or 5 compression strokes. Compression readings should be 159.5-188.5 psi (11.2-13.3 kg/cm2 ). If compression builds up quickly and evenly to the specified range on each cylinder, compression is normal.