as jesse says there are extra oilways that over hang the block of the cvh. i did try to sort this out years ago. with a 1.8cvh block (which has the same head gasket template as the 1.6) and a 1.8zetec head. youll be pleased to know that all the passages line up with each other. SO... what ya need to do is have a de-compression plate made, thick enough to take a union fitting and return the oil to the sump. then ya need a zetec head gasket and a cvh head gasket to mate them together. then you can runn silly boost on a small 16v unique engine. youll also need to match up a cambelt of the right length to take the extra pulley. however the crank in a cvh has been known to bend/break at 300+hp, whereas the zetec one will take significantly more. hence i gave up on the idea, it was too much work for little gain, and just n-a tuned my 1.8cvh.