I have not seen this topic covered - Does the Ring of Curing stack with the Enhanced Cures for the Life Oracle? The wording and different sources lead me to believe that they would stack and work together. Hopefully, someone official can look at this.
Below are the excerpts from the item and the class SRD material.
Enhanced Cures (Su): Whenever you cast a cure spell, the maximum number of hit points healed is based on your oracle level, not the limit based on the spell. For example, an 11th-level oracle of life with this revelation may cast cure light wounds to heal 1d8+11 hit points instead of the normal 1d8+5 maximum.
Ring of Curing: This simple copper ring is a boon to those who spend their lives healing others.
Whenever the wearer of a ring of curing casts a conjuration spell of the healing subschool, all maximums to the level-dependent healing provided by that spell increase by 2. For example, cure light wounds would provide a maximum healing of 1d8 + 7 (at 7th caster level), while heal would cure a maximum of 170 points of damage. This ring does not increase the wearer’s actual caster level, nor the amount of level-dependent healing provided by any such spell
