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Schnook
01-12-2006, 11:24 AM
Just got my shop manual, it says my 96 454 mag is rated @350hp. Ads and posts I've seen put it @330. Which is correct? Is the difference that they are at the flywheel and prop? Am I reading the manual wrong?

blackhawk
01-12-2006, 12:42 PM
Just got my shop manual, it says my 96 454 mag is rated @350hp. Ads and posts I've seen put it @330. Which is correct? Is the difference that they are at the flywheel and prop? Am I reading the manual wrong?

Very well could be prop hp vs flywheel hp. HOWEVER, shoudn't a 1996 454 MAG be a MPI motor with 385 pshp? :confused:

Schnook
01-12-2006, 02:33 PM
I have no idea. My outdrive says 454 magnum on it and it's got a holley carb. Maybe not the original engine? Is there any way to check this?

zimm17
01-12-2006, 04:35 PM
Stick your head past the distributor and get the the serial number off the top of the bellhousing. Then go to mercruiserparts.com and look it up.

Check you intake manifold to see if it's cast iron or aluminum. If a magnet sticks, it's not a magnum.

My '97 carb'd magnum was rated for 365HP, the EFI model is 385.

mrfixxall
01-12-2006, 05:16 PM
If it has a holly its most likely to have a 365hp mag engine. The 330 hp had a q-jet....Do the intake runners look flat if so 330 hp,if the intake runners are even or a little above the valve cover edge its a 365hp...Show us a pic of your engine i or someone on the board will be able to tell by the intake....

Schnook
01-12-2006, 06:21 PM
Soon as I finish my chores so I can sneak off to sit in the boat and make engine noises! Thanks!

blackhawk
01-13-2006, 12:57 PM
Man, mercruiser made WAY too many engines!!! :confused:
So, Merc made a 454 Mag EFI and a 454 Mag carb with two different hp ratings?

mrfixxall
01-13-2006, 02:57 PM
Man, mercruiser made WAY too many engines!!! :confused:
So, Merc made a 454 Mag EFI and a 454 Mag carb with two different hp ratings?
454 330 hp/454 mag 365 hp/454 mag EFI 385 hp and in the 80's a 425hp//I think:banghead: :bonk: :bonk:

joseph m. hahnl
01-13-2006, 03:18 PM
Stick your head past the distributor and get the the serial number off the top of the bellhousing. Then go to mercruiserparts.com and look it up.
Check you intake manifold to see if it's cast iron or aluminum. If a magnet sticks, it's not a magnum.
My '97 carb'd magnum was rated for 365HP, the EFI model is 385.


my 350 mag has a cast iron intake. What I found is they Slotted the intake bores in to 2 instead of 4. It also has a higher rise than the stock quadra jet manifold.The 454 carby most likely had the same type of modification.But don't qoute me one that . I'll deny I said it because I'm not sure if it's true.

joe

383 BRAVO
01-13-2006, 05:30 PM
From my best knoledge mercruier never used a hollry carb correct? When did mercruiser begin to rate hp @ thr propshaft? Was it before or after 1996?