My new 340 at the track

I don't get where the gain comes from ?
If you go faster at a lower rpm you'll need less gear, so any gain of torque at the crank will be lowered at the tire, end of the day should have similar torque going to the ground.

Shouldn't the hp curve from stall to shift points be the main concern no matter rpm range ?

Long time ago Hensley performance( Ken Hensley) who built my first stroker short block, 25-27 years ago now, told me, because I asked him, how much faster will a stroker be than a stock stroke deal. He told me expect about 3 tenths, maybe a bit more.all else being the same.
I have found that to be true.
Recently, I got to test that myself. I had a stock stroke 360, best it ever went, with the current trans and convertor was 11.31.
I had my current 418 built( by the same shop) one big difference was compression. 360 was 10 to 1, 418 is 12 to 1
I swapped same convertor, transmission, headers, and entire top end( including the cam, which I still run) and the car went 10.77.
So, two differences, compression and inches. The compression definately would make a difference, no doubt. But the car picked up 54. No other changes.
It has since had heads and headers upgraded, but hadn’t yet regards the above. Same 1 5/8 Doug’s headers and mufflers I had originally, swapped onto the 10.77 combo, were on the 360.
Another way to look at it, look at mountain motor pro stock and NHRA cars. I believe everything is the same except the inches. Substantial difference in performance. Those cars run well over 220.

Edit, the new combo I did change the intake, but initially didn’t with the comparison above.