This is being sold as a rare classic locally.
I agree with the claim of "very few left".
He could also make a claim for their OFF ROAD capabilities, that's where I saw most of them, usually 3 or all 4 wheels off the side of the road.
I guess everything becomes classic at some point, but your...
There's a guy on the 80's forum who makes them, I think he cuts panels for 60's too. Por15 coated steel with sound deadener on the back, new fabric on the fronts, and I think you use your own hardware.
Normal day to day for me is 12-13, if I get real gentle it will give almost 15. desmog made an improvement in acceleration from low rpm, but didn't affect mileage that I could see.
The trucks I see for sale seem to have very low mileage for their age and condition. Compared to 25-30 year old Land Cruisers sold new in the U.S., they seem to have half the mileage but equal or worse wear and tear. One of the sellers said it was because they don't drive as much or as far...
If you suspect a cracked head, is it because of loss of power? A compression test might be in order, but pressure testing the cooling system should put your mind at ease, no leak would mean no crack, almost always.