I used classicparts.com They have the filler panels and the seals. FRONT FENDER TO CAB MOUNTING PANEL and FRONT FENDER TO CAB SEALS.
Maybe not purest, but I used rivets to attach the panels to fender prior to final install.


~ HB
1966 Chevrolet K-10 | Ghost: formerly Flappy Fenders | In the Stovebolt Gallery
1962 Chevrolet C10
1962 Suburban