Hi Dennis:
I note that you do not know where John Blake may have come from in County Clare. If you check out the list of surnames from the Tithe Applotment Books (taken between 1823-37), you will note that most of the Blake families in County Clare were from the West Clare area. It might be worth llooking at the parish registers that are associated with those areas: Kilfearagh, Kilballyowen, Kilmurry Clonderlaw, Killard and Moyarta. The Clare Library is a good resource to use. The link is here:
http://www.clarelibrary.ie/eolas/coclare/genealogy/genealog.htm
All the best,
Jane