nope. that is 100% bs. if that were the case, if you take an 84mm built bottom end, and put them same intake mani, Tb, header, and all other parts the same and only change the head from a stock gsr to a stock b16, you would see 15-25 whp difference. obviously thats not the case. so therefore no way in hell.

I'm not saying one head isn't better, just saying its no where close to 10%.