The camshaft lobe lift specifications for the 1988 and 1989 Quad 4 engine (VIN D) were printed incorrectly in the 1988 and 1989 Service Manuals (Section 6A7).
The lobe lift is:
Intake VIN D 8.890 mm (.350") Exhaust VIN D 8.636 mm (.340")
Please make this correction in your Service Manuals in Section 6A7.
General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.