BACKPRESSURE EGR System: Notes

There are 2 types of backpressure EGR valves used by General Motors. A positive backpressure EGR valve (used on Federal V8 models) and a negative backpressure EGR valve (used on some 6-cylinder and most California V8 models).

NOTE: Negative backpressure EGR valves are used on models with relatively low backpressure exhaust systems.