BRP Hotrods have headers that fit these as does Street and performance. I think there may be people on performancetruck have used different headers, but I don't know of any that will bolt in.
I also suggest getting the plates from the same place (check my website project). They put the LS back in the same place as the original SBC. Some companies move them forward, you don't want that. Edelbrock and S&P offer 1" setback (from SBC) that is what I am using on my truck.