This car was bought on ebay by a friend who didn't know not to buy a 350 . It ran from PA to MT but top speed is 70 mph. The turbo was exposed and the fan can be seen to turn, waste gate appears to be closed, but lack of power persists. Can the turbo spin but not sufficiently? Seems like the advise (other than selling it) for turbo problems is to get a rebuilt from turbocity.com or tubonetics.com. Advice?

The car starts great, doesn't smoke until you step on it, and seems to run perfectly. It has 230k, well maintained.

Before we start investing $ into it, should I advise to sell and start over? Thanks for any input, I'm prepared for the worst, just hope the owner is too!