Exactly, isnt it clear Guffy would smash Goku to pieces ....Goku can blow up planets. Luffy can destroy really big rocks. Its obvious.
Crossovers have to make them equal to make up for the power difference. As much as One Piece is several levels better than Dragon Ball, in terms of powers of the characters Goku is stronger without a shadow of doubt.well...as far as anime crossovers go...i think its even... https://www.youtube.com/watch?v=2ktk0RIIMcA