Trough doctor,
I do not know what the cost would be in Canada but here in Southern Calif. (Just north of LA) a good friend of mine just spent just under $7000 US dollars to rebuild a Lotus twin cam (1558 cc "big valve" Lotus-Ford Twin Cam) for his Europe which had been stored for about 12yrs due to a bad head gasket and should be the same engine you have in your 7 less the dry sump setup.
Now you have to remember that the engine you have is only worth what someone is willing to pay for it as they will most likely want to freshen it up and want the entire dry sump setup with the engine before installing it into a car for use so unless you find someone looking for that specific engine setup it might not be worth the change and besides why would you want to get rid of it as your 7 is worth more with the twin cam that is dry sumped than with the Zetec if it is the original engine that came with the car.
Another consideration is will the transmission that is in the car mate to the Zetec engine or are you also planning to replace that at the same time as that will also cause you to most likely have to make a new drive shaft to fit your car plus the transmission and differential.
All of this is possible but is it worth the cost or time, only if you really want to tackle it and just have to have it is it really worth it but that is just my belief. If it were me I would just drive the car the way your acquired it and have fun with it and there are parts out there that will make the engine you have produce more HP if that is really what your after but they will also shorten the life of the engine so it is something you just have to weigh for yourself and use the information that others provide as a guide so in the end it is all about what you want and can justify to yourself and no one else so have fun and keep all of us informed as to the outcome.
:driving: