66 c10 bench seat bottom foam
 

I am recovering my 66 c10 bench seat bottom using the original foam and wondering if it would hurt to add 1" layer over the old foam, has anyone ever done this? The original foam looks a little tired and thinking another layer would help, but wondering if the seat would bind on the sides and prevent the top seat from swinging forward.

Re: 66 c10 bench seat bottom foam
 

I've watched an upholstery guy glue foam to the original bottom foam and then use an electric knife to shape it. Then he replaced just the upper part of the cover and was able to sew back to the rest of the cover. Then he did the same thing with the side panel on the backrest.
You couldn't tell it except for the different grain on the new vinal.

He also said something about using denser foam so it would hold up better.

Short answer, Yes.

Re: 66 c10 bench seat bottom foam
 

Space is already limited in these trucks if you're at or above average height, most guys are cutting the seat mounts down for more room. We've been redoing a lot of 60's truck seats lately and have been repairing any bad sections of foam by cutting the area out, gluing new foam in place, shaping it with an electric knife, smoothing it with a 2" grinder with 36 grit disc, then using a 1/2" layer of Dacron instead of extra foam. It doesn't really add much/any height when you're sitting in it like foam would but helps the cover fit better and look smoother.

https://i.imgur.com/cFpdqbYh.jpg