Hi all

What changed in the 1997 454 Mag carb engines from the older ones to lose 15hp, 365hp to 350hp? Also, its hard to believe they get an additional 35hp from just the EFI, Am i missing something?
Thnx

I don't know that anything changed, I think it may just be the way they were rated (were always 365 at the crank, 350 at the prop).

They are the same engine. One is the crank hp(365) and one is the hp(350) rating at the prop.

Cool, thnx guys

im quite sure more than 15 hp is lost in a bravo drive,i always thought is was more like 30.

I never understood why the 7.4 base was 330 at the crank 300 at the prop while the mag was 365 and 350 respectively. I know the mag has more power and left it at that.

Everyone is correct. Mercuiser used to advertise their engines at crank HP. The base 454 was 330 at the crank and 310 at the prop. The 454 Mag was 365 at the crank and 350 at the prop. When they came out with the 454 EFI and 502 in 1994 they started advertising prop HP. So the 454 EFI is 385 at the prop and the 502 is 415 at the prop.

True for sure.
I think Merc was just trying to make the numbers look better.