New seat foam question… again.

[HO455]

I'm sure the problem lies in the stiffness of the foam as 72c20customcamper stated. Foam comes in many varieties and no one knows what stiffness GM used back in the day. (Except maybe the Grumpster, bless his sole, may he rest in peace)

If I was you I would remove the bottom inch of foam and replace it with a softer foam so the foam collapses down more when your seated but still looks right when no one is sitting on the seat. If 1 inch isn't enough then replace 2 inches off the original foam height with softer foam.

Heck we're luck to get aftermarket parts that are close to the right size let alone being made of the correct factory material.