This is false. I had a 408 with good aluminum heads, solid roller cam, etc and swapped in the less desirable pre-eagle 5.7 with only a cam and some home porting on the heads. The 5.7 went faster in the 1/4 than the 408. Same car, same weight. I'll repeat, that was a stock early 5.7 with a cam that makes more power than a built 408. If you put the same money it takes to build a stroker small block, you could have an easy 650Hp Gen 3 hemi than runs on pump gas.
I'll go ahead and address the forthcoming comments that say they can build a stroker small block to make 650HP. I'm sure you can, and I doubt you will run pump gas. And The build cost will go up substantially. So that build cost, and your G3 hemi will now make 800HP and still run on pump.