Jennifer,
I have had a look at the maps for the Lurgaboy and Altaturk properties. The Lurgaboy farm still has building son the site which look to be inhabited, judging by the condition they are in, on Googleearth. Whether they are the original buildings is less certain but the house is in the same location as the house on Griffiths, so it may incorporate the old buildings. The property is at the very end off a lane from the A28 Markethill RD. Travelling north the lane is off to the left between Drumatee Road and Gosford Rd. The lane doesn’t appear to have any name and so the properties on it probably have Markethill Rd addresses. There 3 houses fairly near the Markethill Rd and then the lane splits with a property off to the right. Carry straight on till you get to the end of the lane. It turns left before finishing at the old farm. There are no vehicles outside the farm on Googleearth. Possibly it’s just being used as outbuildings nowadays. However you’ll know when you get there. If it’s not occupied, ask at the houses up the lane, someone there will know who owns it now.
I checked the Valuation revision records for Altaturk. James Porter acquired that farm in 1878 and it then passed to Alexander in 1880. The main farm building was on plot 5, though as I mentioned previously he also had some other land in the townland, on plot 3.
The property today is on the Altaturk Rd. (That diverges from the Hamiltonsbawn Rd). However I am not certain precisely where your farm was. The maps on the Griffiths site have had plot numbers changed at some point over the years. I don’t know when. So, for example, if you look at the map you will see that what was originally plot number 6 has been renumbered as 5. 4 has been renumbered as 3. So precisely which plot was your ancestors is not something I can say with any certainty. My advice would be to drive along Altaturk Rd till you come to the point where the old railway line crossed the road. You’ll need to look carefully for it, as much of the track bed has been reclaimed as agricultural land. Then knock on a few doors around there and see if anyone can direct you to where the Porter farm was/is. Looking at Googleearth, I am not certain whether there are any buildings still standing but, as I say, I may not be looking in quite the right place.
http://www.askaboutireland.ie/griffith-valuation/index.xml?action=nameS…