So where is this car? I call dibs on it if it's in N.W. Ohio... The 262 Bertone was only made for a few years 1978-81 I think and are pretty rare. Only a few thoundsand were imported into the U.S. from Bertone in Italy. IF the PRV V-6 still runs OK $500 is a bargin. Yes the V-6's were troublesome. Soft metal camshafts wear out early and head gaskets blow out too. I have heard of a few people here who have never had any problems with theirs. There are rumors of the late 80's Renault Premier and the Chrysler Eagle Premier V-6 heads being swapped onto this motor. I don't know anything about this. But there is a rally car on this page that runs a turbo version of this combo. You could also swap in a B21 or B23 drivetrain if the motor is no good. I do know of one 760 that had the B230F-turbo motor swapped in place of the V-6. Also the PRV V-6 is the same motor that powered the DeLorean. Must have been fast in order to go 88 MPH to engage the flux capacitor and travel throught time. All of the rust you described are in the common 240 locations and are ealily repairable.
Ben