I have never worked on a /6 so I don't have any first hand experience, but I stumbled on Uncle Tony's Garage on Youtube. He has a couple of episodes on the /6 and has some interesting ideas, I don't agree with everything he says sometimes but I think its a good place to start if you don't have any experience with these engine and take away what information you want. Do a search there are several episodes on the /6. Here are a couple episode:
