I may be showing my ignorance a little here, but I did not think the turbo pickups came out until 86/87. Of course, a turbo engine could have been retrofitted into the truck. Are you sure it is a turbo? Maybe the oil line to the alternator (combination vacuum pump/alternator) cracked instead of the turbo oil line???

Either way, as long as the oil level did not get too low, neither component going out should not have crippled the engine permanently.

For turbo rebuilds, see:

http://www.majesticturbo.com/index.html