ZVH Engines. The "ZVH" engine is a Ford Zetec bottom end (1.8 or 2.0 litre) with a Ford CVH head fitted. To fit the head to the block there are 3 problems to overcome - 1) Compression ratio. 2) The redundant oil return passages in the Zetec block that need to be blanked off. 3) There is a waterway in the Zetec block that sits very close to an oil gallery in the CVH head.
A copper decompression plate will tackle all of these 3 problems in one go (assuming this is a turbo engine), and will allow easy fitment of block to head. If you have already sorted out issues 2 & 3, then a (cheaper) alloy plate can be used.

found @ http://www.ferriday.co.uk