Something to remember...we don't RACE flow benches...Flow numbers are not the last word either...It's the WHOLE COMBO, regardless of what cylinder head, intake setup, and camshaft you use, it has to work together. I've seen TFS headed cars fly, and I've seen some that were so-so...I've seen AFR headed cars that ran very well, and yet I've outran a few with very similarly modded cars with my old "lame" Edelbrock headed combo...

Like Grim Reaper pointed out, just because two cars make 400hp, doesn't mean they'll run or perform anywhere near the same...there's TONS of other variables. I had a 502rwhp 3540# 86 Mustang that went 10.24@133, and a buddy's 503rwhp Mustang ran 11.80@118, LOL...Two totally different engine combos tuned very differently.

The power difference:
Mine made 543rwtq, his made low 400's....yet he made BIG HP dyno numbers he could brag about...which as we see, don't mean diddly.