Foam question

[vintage23]

I'm restoring a 1976 inboard cc. I'm removing some wet foam, do I need to replace the foam under parts of the floor? The wood stringers are good and I just redid the floor using coosaboard. I didn't want to cut the bottom skin of the original floor so I didn't remove the foam before replacing the floor. I gained access from the sides of the engine compartment and pulled out wet foam. I really don't want to replace it. Will it affect much? Thanks!