Help installing 1965 Barracuda carpet

I used the 3M super 77 spray adhesive to install the carpet in my cargo area on my 69 which is similar. Blob it on thick near any unsecured edges or use some 3M black weatherstripping adhesive on the edges. Mine came loose on some of the edges. Make sure you have good ventilation using the adhesives. It takes awhile, I removed most of the sheet metal back there to install it.

As pista has said, while you have the carpet out, it is good to add some sound deadening stuff. I used a Dynamat clone from Amazon called Noico. It really quiets the car down a lot. I stuck it everywhere I could get it, except for the cargo area sides. Probably should have done that too.