I run factory iron on my 340 and it'll blow the doors off every 340 I've riddin in, I also had my ported j's on my stroker w/dual plane and small'ish '.533@the valve' solid cam and I heard people saying that to them it felt like a 500hp car...
those who say these heads are door stops don't know what they are talking about and that should say something about their judgement.