Hi Dan. I wish I could have found a service manual for my 380 sel too. I had to settle for the cd which covers th 126 class. Also, when you purchase your new head gaskets, they will have the specific torque pattern as the moderator described above. I pretty much did the same thing you are doing; I had to convert single-to-dbl t-chain. A copy of this can be attained via the dealer, or you can get the internet version from ebay. The diff in $ is about a 100$ but the quality is lacking; you get what you pay for. There are however, written manuals that some service people have that are probably worth a substantial $. With that said, us average folk have to settle for whats we can get! Finally, don't forget about the tools you will need. Search the internet: you will need a guide-rail pin puller as well as the special, extention sockets to remove the head bolts beneath the cam. Keep us posted; I could have not done my job w/o this site. les