They did a 383 Chev vs Mopar and tried to keep them equal as possible, down low the mopar won, above 4,000 rpm they basically had same curve.
Start turning them above 6000-7000 rpm the that's gonna be a different story.
I get why people do a 408 but never made too much sense to me, since we got 383/400/413/426 all great 400 ish cid engines even a 361 (4.125") with a 3.75 stroke gets there. And you don't have to worry about underheading the engine.