My new 340 at the track

I don't deny that the average stroker finds a performance increase, but I feel it's more from some secondary effect, like DV says 383 Chev always make more power than a similar 350 Chev but he attributes that to a 383 can build cr with flat tops not from added displacement (not saying he's right).

To me problem is what's a fair comparison between 360 vs 408 (or whatever engines) if built with the same parts obviously the parts are more than likely gonna favor one over the other, the parts should be tailored for each engine but when parts are different what's considered equal build ?