I'd say 5K would build a reliable turbo single cam. The AFI system listed looks good. You would need the kit plus:

PIstons and rods: FJ Distributors $600
Clutch $350
ARP headstuds $100
Injectors $350
ECU/Engine Management $200-$1000
Tune $500

Comes to a little more than 5K, assuming you install everything yourself.


Edit: add machine work too $200