Most people seem to think highly of Doug Thorley headers. I have no experience, so I cannot day for sure. I will advise against the JBA headers Summit sells. The quality isn’t terrible and is commiserate with the price/point, but THEY DO NOT FIT!!! My truck is a 91 suburban 2500. It took me cutting the frame AND heating and beating the tubing to get these headers to fit. Whatever brand you go with I would advise a serious examination of their return policy prior to purchase.
Jeremy