Im building a E30 m42 head but I would appreciate any suggestions, in a mild built head. I am going to use the vw lifters I found the part number for them. I wanted to know about using the 6MM valves from the E36 m42... are they a direct swap with the 6MM valve guides? I know the valves are the same size but is the length the same? also what other parts would I need. are the valve keepers different? any one help ?