[olddog]

Considering that they were able to get 450 Hp out of the 289, and they were doing this by porting the cast iron heads, going to a longer stroke 327ish engine would likely not make any more power. It would likely just make the same Hp at a lower rpm. Since the 289 was standing up well to the rpms they were turning them, there was no need to do this and the rules of the day may have limited them to the factory displacement. Had there been a need for more displacement, those engines would be everywhere. A research item here or there makes sense. You have to always be looking for an advantage.

This is just an observation and a personal opinion. I could be wrong and have been several times.