Interested in buying a drop in motor for a project I have
I have the serial number for the motor ,I'm trying to figure out what
HP 454 it is ,I've tried online serial number breakdowns and it
Doesn't provide the HP just the year and cubic inch.i spoke to
Mercury parts direct ,the gentlemen I got on the phone wasn't to confident
In his answer and not very convincing ,I'm curious to see if it's a 330hp or 365hp .maybe someone here could help me
Here is the serial # Oc675728 .any info would be greatly appreciated.

PPT says its a 1989 454 mag with bravo - i believe that is the 365hp - do you have the motor? 365 mag should have alumn intake

https://www.perfprotech.com/mercury-...earch=Oc675728

The gentleman has it listed as a 454 magnum ,not sure on the intake ,but if I remember correctly the 330hp was a 2 bolt main with the small port heads and the 365 has the 4 bolt and the rectangular port heads.
I want the 365hp ,I called mercury parts direct they told me it was a 330hp then called a mercury phone number that I got from searching around they told me it was 340hp .im just trying to get a solid answer before buying this motor

1989 Mercruiser 454 CID had a 340 hp for the Blue Water inboards

and they had Bravo Series for Bravo one and Bravo two was 330 hp

Then they had magnum Series - 454 mag was 365hp

then they had Performance products HP 420 was 420 hp

again this was for 1989 and the 454 applications across the board.

1986 and 1987 the 454 Mag was 330 hp that used a Alpha one outdrive - there was no Bravo outdrives for those years. Bravo came out in 1988 model year FYI.

My 1989 7.4 Bravo had flat tappet, 4 bolt, cast internals, 3/8 rods, small oval port (peanut port) heads, 330 HP

using same link above - i used my serial #OD607436 - it shows sames specs - 1991 = 454 magnum bravo (mine is a 1992 boat & is the 365hp)

some 330hp had 4 bolt mains - but small heads, rods, etc