[67c10rustbuket]

Im with Mr Chevrolet. Don't use the "cover", the correct piece you should use is called "rear cab support" which is also sold by Brothers Trucks and well a lot of others. cut to fit as much or little as you need.

Once you dig into the truck you should expect the worst, These trucks are very good at rusting and everything ties together at the cab supports, so for the rear cab support replacement I would expect to also replace: partial floor/inner rocker, B pillar, and cab corner. Hard to say without pics though you may be lucky. There are a lot of people who have done this and have step by step progress pics in their build threads and in the FAQ section if you need some direction. (pics work better than words for me). I could link some for you or tell you where to look if you need. Good luck! Later