200,000mi isnt a problem for most modern engines, even the turbo kind. The Fox3 and SN95 crowd will tell you that 5.0s easily go that far with little trouble. A few of them even boost those high mileage engines.
I havent done any actual calculations, but I would expect a project like this to be in the $1500-3000 range. A decent running TurboCoupe, SVO, or XR4Ti engine/trans pullout should be 1000 or less. Its a big bonus if you can get the harnesses and computer included. You'll need the T5 crossmember and either a cable clutch conversion, hydraulic conversion, or the right bell/fork to use the stock linkage(you want a manual, right?). Then modify the fuel system for EFI. If you could get the whole donor car it would be alot easier. The rear end is popular with Fox3s because its a disc brake 8.8 with either 3.55s or 3.73s. Drivable TurboCoupes I've seen are $1500+. Even with a stock 2.3T, a '65-66 should be faster than a premium fuel 289.
I plan on doing something similar with Pinto in the next year or so.