Here is what you aren’t getting. Since we are talking about are under the curve, you are talking about WOT.
What I’m saying is the numbers you see at WOT do not translate to part throttle mid load power.
You (and most others) assume or suppose is a better way to say it is that what you see at WOT is what you see at part throttle.
For example, at say 2500 at WOT you have 400 TQ and the smaller engine makes only 325 TQ.
Is there still a 75 TQ difference? No, there isn’t. Partial throttle openings reduce that difference.
This is easy to see on a dyno where you can control things.
And I know some will argue there is still a difference and the bigger engine will still be making more torque and that’s correct.
But…you still have to account for gearing. And not just the rear axle ratio either.
At some point, you end up with gearing most guys wouldn’t use and then the gap between the two engines performance gets wider.
Looking at WOT area under the curve and correlating that to part throttle area under the curve isn’t what happens.
And, as either engine starts making more power the tune up window gets smaller and you have less room for errors in tuning.
The engine with less stroke (or even the same stroke with different bore sizes like the 273/318/340) will have a smaller tune up window sooner.
They are certainly less forgiving once you start getting to 1.3 HP/CID.