Do I need to disconnect positive when charging V8 5.0L battery?

I would. But disconnect the negative battery cable first, then the positive. When you hook the battery back up do the positive cable first then the negative. I did this exact same thing when I charged the battery in my 2000 Grand Prix on Sunday. With the electronics in vehicles of this era I think it's better to disconnect the battery when charging to avoid a power surge. Jump starting and newer vehicles are a different story. Many newer models can't have the battery disconnected or the computer will need to be reprogrammed. Hope that helps! Jim

Thank you, Mark, I have been disconnecting pos only, on the advice of a friend. Will now do both until I replace battery!

You're welcome. Glad to help! Jim