i called Mercury racing about this when I ordered my boat with a 525 EFI...my insurance agent said because it was OVER 500HP that it was going to cost me more, so I wanted to get to the bottom of it to try to save some $ on my insurance premium...here is what the Mercury racing rep told me...basically the 525 EFI has 525 HP at the crank, but 500 HP at the prop. Hence, I assume the 500 has 500 hp at the crank and 470 at the prop.
So does anyone know the true hp of the 98 500 bulldog(540 ci) Merc manual shows it at 490 hp at the prop. What is the crank hp? Called Merc and they would not give me a true hp rating. Was told they had to be at least 500hp, but would not give me the dyno sheets for them.