330 horse 454 upgrades to 420hp merc specs
08-24-2025 | 08:13 PM
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From: Surprise Arizona
330 horse 454 upgrades to 420hp merc specs
Hey guys! This is my first post on here.
I recently purchased an 88 Mirage Intruder 270 with twin 330 horse 454’s. It’s a running project and I got it dirt cheap due to circumstances with the owner moving. I’m stripping the whole boat down to restore and re gel it and possibly do the transom. While I have the engines out I want to refresh them and upgrade them similarly to the 420 horse merc 454’s. I have a pair of 049 heads I plan to use and I’m looking to have custom ground cams to the 420 horse cam specs which was the 132561 (no longer in production) and pair that with a good intake manifold. I believe the cast crank and rods should be fine for my application with upgraded ARP hardware on the rods, but I am unsure about the cast pistons and may want to go forged. Does anybody have a build list for a 330 merc to get up above 400 horse? Not looking for anything over 420-450. I want to keep the motor able to run 87 or 89 at the marina so nothing too high compression and keep it reliable. Just want a little more power on tap. If anybody knows an already available cam that’s similar to the crane 132561 that would be awesome as well.
I recently purchased an 88 Mirage Intruder 270 with twin 330 horse 454’s. It’s a running project and I got it dirt cheap due to circumstances with the owner moving. I’m stripping the whole boat down to restore and re gel it and possibly do the transom. While I have the engines out I want to refresh them and upgrade them similarly to the 420 horse merc 454’s. I have a pair of 049 heads I plan to use and I’m looking to have custom ground cams to the 420 horse cam specs which was the 132561 (no longer in production) and pair that with a good intake manifold. I believe the cast crank and rods should be fine for my application with upgraded ARP hardware on the rods, but I am unsure about the cast pistons and may want to go forged. Does anybody have a build list for a 330 merc to get up above 400 horse? Not looking for anything over 420-450. I want to keep the motor able to run 87 or 89 at the marina so nothing too high compression and keep it reliable. Just want a little more power on tap. If anybody knows an already available cam that’s similar to the crane 132561 that would be awesome as well.
