I just went through this same thing on my 53. So I am trying these from the filling station and it promises to be the cure.
https://www.fillingstation.com/detail/25060/Chevrolet_194755_TRUCK_DOOR_EDGE_SEAL_THIN_12.html


1953 Chevrolet 3100
261 cu inch, sm420, 3.55 rear, torque tube still,omaha orange, still 6 volt, RPO green glass, side carrier spare, all done
In the DITY Gallery
Video of the 261 running

1964 GMC 1000
305 Big Block V6, sm420, the next cab off restoration