Stock 340 dyno tests?

Note that when the 340's compression ratio dropped two full points and got a smaller intake valve, it dropped from (supposedly) 275 gross hp to 240 net.

The 318 went from 230 gross all the way down to 150 net with NO loss in compression.

Draw your own conclusions.
The 318's 230 hp rating is grossly exaggerated by the factory, 340 wasn't. That's why they were made to switch to net.