1977 18sf vs 2003 20sc

[dginge]

I understand light engines on potter built boats are imperative, I own an 18sf with a 2stroke 150hp. It runs great but it will always be an 18 foot boat. I have a family of 4. Correct me if I'm wrong but aren't the (2000's) 20sc WITHOUT COFFIN BOX made to take a larger more modern engine and still built on the exact 20 mold? It's a different cut out and transome height. Thanks