If you do your own work, the maintenance costs are low. Once you have it sorted, you mostly just add gas, check
oil, brake pads, coolant, etc.
The engine is American (351C). The second most popular is 351W (392, etc.). I've seen or heard of 429/460, 427FE, BBC, SBC, 302 Ford, and even Chrysler Hemi.
The trans is a ZF 5-speed. It is expensive to repair (avg $5K), but they are very strong and reliable.
The rest is very cheap, but you need to talk to the Pantera group to save a lot of time finding parts. The rear wheel bearings, for example, are an enclosed ball bearing design. If you go to Autozone, they'll shake their heads. If you go to a bearing supply store with the correct part number, they'll sell all 4 rear bearings for under $100. The front wheel bearings are the same as 67-69 Mustang. Once again, if you go to Autozone and ask for bearings for a 72 Pantera, they'll say, "What?" If you say, 67 Mustang wheel bearings, they'll have 'em.
On the other hand, if you don't do your own work, you could spend a lot of money educating the local mechanic.
And if you want to check one out, there are owners all over the place (even Hawaii, Sweden, Canada, Japan, and Alaska). They'll even let you drive one. They are just as cool as the Cobra owners.