I need help with beating the elite four on pearl my team is infernape lvl 52 gyarados lvl 63 venusaur lvl 54?

a lucario lvl 51 palkia lvl 50 and a staraptor lvl 55. infernape:fire blast,fire wheel, fire spin, rock smash. Gyarados: Hydro cannon, hyper beam, surf, waterfall. Venusaur: razor leaf, solarbeam, strength, synthesis. lucario: dragon pulse, copycat, and two others i forgot sorry :/ but they were normal kind. Palkia: spacial rend, dragon pulse, thunder, and something else sorry i forgot that one too :( but i got to the cynthia and lost to her last pokemon fyi