pump size

Hello

i need to replace my pool pump century CAT B2853 1 HP and my housing is pentair 342853 pinnacle PFII-P1-.75A

my pool Size 24500 gallon  only have 1 Skimmer 50ft and wall suction 70 ft  and sand filter SD60 .

Should i buy 3/4 HP like the Housing OR 1 HP like the motor ?

thank you