My father is considering purchasing an '85 F250, 6.9, 5 speed. It has 390,000 km's on the odo, and the story is that it was never winter driven. It has an aftermarket turbo, and I'm concerned if that will shorten engine life. The selling price is $3800.
Any feedback on the turbo query would be appreciated.
If the turbo is working properly and not overboosting then its not gonna hurt the engine. I'd LOVE to have a turbo on mine. A boost gauge and a pyrometer would be my first investment if you buy it. As long as you keep the EGT (exhaust gas temp) down it will be fine. Too hot can burn holes in pistons.
A turbo will not shorten the engine life, especially if it's been babied. That 5 speed may have been swapped in, which is a good thing.
The biggest thing for you to check, is to make sure it will start when cold. Tell the guy you want to come look at it and hear it run, and you want to be the first one to start it that morning. If he refuses, then it has a few problems which can be fixed, but should lower the asking price. Before you start it, feel the engine, it should be cold to the touch. If it's not, and he swears he has not run it, then he has had it plugged in overnight to 120v, and this is another sign it's not going to start without some help.
This is a good setup to have, and gets very good fuel mileage and makes a good truck. You will not be able to buy the magazines off the shelf and buy all that stuff they sell to add power, but if you want a good reliable truck, this is the one to have.