I have 496 mags in my boat,I have also seen 496 HOs and I just saw a boat that had 496 mag HOs,
is there 3 different 496??I always thought it was 496 mags and 496 ho,
whats the differnce in in the 496 mag ho with the 496 ho

The Merc Service Manual lists two 8.1L.....496 MAG with 375 HP, and a 496 MAG HO with 425 HP.

Cam and computer program.

so there only a 496 mag and a 496mag HO there is no 496HO

The service manual doesn't list a 496HO.

496mag=375hp
496mag HO=425hp

Same engine except for the cam and ecm..........and merc price tag.