my s4 t2 rear iron has about a 1 inch section of the outer water seal groove wall on intake region that is about .055 inches thick. Would this be okay to use in a rebuild?

 

outer water groove wall? should be fine...... picture?

 

Not my rear iron but an example to show what I am talking about.
[IMG][/IMG]

 

since it's on the outer coolant seal groove, you should be fine. only really need to worry if it was thin on the innner coolant groove. if you're really worried about it, you can try to build that section back up using steel putty or some JB weld.