[jubba]

does Ea for the reverse reaction - Ea for the forward reaction = enthalpy change for that reaction?

[Byrne]

does Ea for the reverse reaction - Ea for the forward reaction = enthalpy change for that reaction?

That is correct.  In an exothermic reaction, remember that the E_ar will be a negative value.  If E_ar is a positive value, the reaction is in the endothermic direction.  If you're having trouble understanding why this is, draw a potential energy diagram or just view one at the following linl:

http://www.saskschools.ca/curr_content/chem30/modules/module4/lesson4/potentialenergydiagram.htm