For most practical purposes a 20r heap swap is not worth the trouble. Don't believe all the hype.
Have you built a hybrid? I'm guessing no, because I have and I know your statement is pure bull. I did it with a stock block and stock 20r head, no big valves, and I can tell you it was very worth it. The 20r head is a better design, period, and the 20r intake manifold breathes way better than the old 22r heads. I've never had a 22r that wanted to rev at all, but when I put on the 20r head it came alive. No I didn't gain 30hp, but it pulled better everywhere and pulled the long steep hill going to work without losing speed, something it NEVER did before.
Not my 2 cents, my factual real world experience.