340 - I have a 73 with the same seals needing to be done. I have the seals from R/T and they look like they have a small retainer tab at the bottom. Once this is released you slide the seal up as you lower the window. Ted said it right - leave the metal retainer on the glass. You may have to "glue" it back. What I did to glue mine on was use polyurethane and push it bacl on to the glass. she aint going anywhere.