I believe the B280 is the third production version of the PRV engine, and has sorted out the problems of the earlier ones, such as camshaft oiling. But they couldn't overcome the bad reputation of Stages I and II, so no one wanted it under the hood. And they were a miserable thing to work on. The designers didn't give much thought to ease of repair and maintenance.

As for the 351 Windsor - as you know, this is essentially a 302 (5.0) with taller deck height, so a lot of the 5.0 performance equipment fits, such as camshafts, aluminum heads, exhaust headers, etc.