If you check the specific gravity on those batteries I'll bet you will find that is well above 1.246, the value of fully charged batteries and as a result the voltage will be a bit high. That is a result of losing water to disassociation. The electrolyte is concentrated.

Usually the exposed plate surface is dead. If it is 20% exposed then you have lost 20% of the original capacity.

I would replace them with Group 31s. That will give you about twice the CCAs.

David