The difference between the PRV-6 and the 4-banger will be immediately obvious upon raising the hood.

The 262's used the B28F.
The B280F, an updated and supposedly improved version of the 28F, is found only in the 760 (not 760 turbo-that's a 4cyl B230F turbo). IIRC, the B280F was the only incarnation of the PRV in a Volvo that had electronic fuel injection.

The consensus on the board is to avoid both of these motors (especially the former) if at all possible. They are not nearly as reliable as the the "tried and true" 4-cyl red blocks, they yield horrible fuel economy, and their performance can be described as lackluster at best.

If you are really interested in dropping a Volvo motor into your Peugeot, you would be best advised to look for a low-mileage B230FT from wrecked late model 940. This motor produces over 160hp and 180 ft.-lbs. of torque stock. The B28F cranks out a less impressive 130 ponies.