C 20 3/4 Ton Pickup 2WD V8-350 5.7L VIN L 4-bbl (1983)
Crankshaft Position Sensor: Description and Operation
On all models with full function systems except V6-229 (1983 - 84 VIN code 9) engines, the ``R'' terminal on the 7 terminal ignition module provides
reference pulses to the ECM indicating engine RPM and crankshaft position.
