W-series Cylinder Head and Cylinder Head gasket Differences
Cylinder Head:
On the new W-series motors, three (3) new water galleries were added to each cylinder head (at the exhaust side). These match the new galleries in the block. (see below)
Cylinder Head Gasket:
Three new holes were added to the gasket on the exhaust side, and the six holes in the intake side of the gasket were decreased in size.
Cylinder Head Gasket Identification:
The tab shape can be used to identify the modified gasket from the non-modified gasket. (See illustration.)

Sources Used on This Page: 1988 Nissan 300ZX Factory Service Manual, Nissan Technical Service Bulletin Number TS87-191 Date: December 28, 1987