This plate blanks the troublesome exhaust emissions hole in the bottom of the exhaust ports off on V8s when the emissions air injector & rail are removed from the engine along with the pump & pipework - this is the rail under the exhaust ports / manifold flange, the rail connects to the air pump.

The air injector emissions system is normally removed when the pipework is rotten.

8 of these plates per car, these plates are electroplated for appearance & anti corrosion, we suggest that you use new copper washers for reliability & spring washers under the 2 nuts per plate