340-360 vs 408-414

No, they didn't. They were fine for a 273, and 318, IF they had've built a 4bbl 318, and put effort into making them build power, other than marine, the 327 would've been outpowered, with the 318 using the small port heads..(factory speaking).. You have to remember, we had 361's, and 383's in place of the 340 and 360 back then. A body cars were the only line that suffered.

In all reality, the REASON why the 273 ran better than the 283, was because of the smaller head design. (among other things, rod ratios, etc) but still.