Stock castings the 426 has almost unlimited horsepower, the wedge not so much, the heads just do not flow anywhere near what the Hemi's do. Wedge block is good for what, 600HP before it breaks, 426 Hemi at least double that.
So you want your wedge to make big power so you need an aftermarket block, heads, rocker gear etc. Same cost as Hemi aftermarket parts.
They're both great engines but different.
Most people have never driven a Hemi, a stock 440 car still pulls okay when you punch it in high gear, a stock 426 Hemi pulls like gangbusters in high gear and feels like that wedge does in low gear. 440 is a great torque engine, the 426 Hemi is a great horsepower engine.

Sheldon