Ok, I look at it this way, Lets just do it like this, We take 2 vehicles the same make model, for instance, i'll say 2 twin 78 blazers, 2wd. 1/2 ton, They are both identicle, same trans/gears/tires even the color, we weigh them & make sure they weigh within 5 lbs. of each other. Now 1 has a 350 4br. with 245 hp & 305 ft. lb. torque, the other has a 400 4br., it has 245 hp & 365 ft. tq., now we know the extra torque is in the CI increase, but the HP is rated the same, remember most of those 400s where rated just as low on HP #s as the 350s in that era, even lower. What blazer will run faster from beginning to end.
The reason i use this as an example is i had a 78 blazer 2wd. 400, it was a stocker, there wasn't a stock 350 around that in a truck/blazer that would touch it (stock vs. stock), but like i will say, thats just my opinion, not that it means anything. Thats why most love CI, its not so much the HP, its the added torque, thats what slams you back in the seat & "keeps you there"