Interesting conundrum , maybe someone can shed some light on it ,the VX cylinder head belonging to 75coupe clearly is part no 5936188, yet my parts microfis , dated 12-1984 only shows 5881825 for the VX head , I have a VX too , so I have since had a look , and yes it is the same as that of 75coupe 5936188, so just wonder was there a later revision ? or maybe just an error in the preparation of the microfis ??