You could try using something like this:
local cf = CFrame.new(0,50,0);
function cframeToTable(cf)
return {cf:GetComponents()};
end
function tableToCframe(t)
return CFrame.new(table.unpack(t));
end
-- Both print 50.
print(cframeToTable(cf)[2]);
print(tableToCframe(cframeToTable(cf)).p.Y);