Be aware that an 036 P/C is not a direct drop on to an 034 case, and may be problems mixing and matching 034 cases and 036 cases. Even mixing and matching case halves from the same model Stihl can be problematic because of the varying deck heights.
nmurph has far more experience than I do, but I kinda think he's wrong here.
Edit: There are little problems that crop up, but not with the case. The 034's engine shroud won't fit over an 036 cylinder without modification, and the 034 muffler will require a couple of spacers at the bottom corners if used with an 036 cylinder.
My experience level: I've done exactly one of these conversions.