I did the same work on a 560 SEL engine. Shortly after disconnecting the fuel cooler lines,the fuel supply line was leaking fuel. After removing the gas cap the fuel stopped leaking. This prompted me to reconnect the the 2 fuel lines after the rocker cover was removed. I didn't think the fuel would travel uphill from the tank, but it did. There are some very good posts on timing chain work on this forum. Go very slow and take your time. If you need parts call PHIL he is very familiar with the parts you will need. GOOD LUCK