Yet again more W2 360 talk

I have thought about having the heads welded up to be closed chamber when I send them in to be repaired. (Now I realize 100% that I can just buy new heads for way cheaper but the whole point of this build is to use sentimental parts I have so that's why I am going the route I am on) maybe with the welded up close chambers I could reached 12.5:1 or even 13:1? Thoughts?