Boy Ralphy, that is a lotta words to say nothing. So your basic point is 261's aren't that much greater than a 235. Is that really what the guy was saying? I believe the guy was saying 261's were less dependable and 235's better.
All things being equal the motors are almost identical with the 261 having more cubes and more hp. It has an different casting for the block and reinforced internal components. For many larger trucks the 261 was the largest motor you could get.