Upper service limit: 165 psi
Lower service limit : 110 psi
Piston upper service limit: 85.920mm
Piston lower service limit: 85.902mm
On the piston, you can take them to a machine shop and have them magnafluxed to check if they have weakend, HOWEVER... I personally just pick up a new one. It's not like the big 5'er goes through alot of topends.
Unless you're Rick