Originally Posted by pdfbt40

I'm sorry, but for a Blacktop, from both personal experience, and that of others, you are incorrect.

The blacktop heads have a part number cast on them,which can be used to identify the different year types and engine capacity/combustion chamber volume. There is no stamped mark except on FRS and ST170 (obviously different). Only the blocks have the capacity 1.8/2.0 clearly cast on the outside.

The combustion chamber of a 1.8 head is 4cc smaller than a 2.0.

A friend of mine sourced a head and had it ported for a supercharged engine. It was only after it burnt a piston that he checked the CR and discovered it was a 1.8 head.

Concerning US heads, again anyone who has buit an engine using American rods and pistons has found that the CR is not to the quoted spec in a European engine. For example a 8.0:1 piston will give 8.5:1 with European heads.

Martin