thinking of buying a merc 420/425
#1
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Lets say I am thinking about buying a old 420/425 merc and using it in a bravo application. I currently have a 330 454 with bravo 1.
From my research I will need to use my existing bellhousing, flex plate, and starter. I am fairly sure that my shift bracket will mount to the riser with a bracket and keep it in the same location. I also think my throttle cable should work with no modifications. Oil filter may have to remote mount.
What else am I over looking?
But before I did all this work above and take out a perfectly good 330hp motor what should I consider doing to the 22ish year old 420/425.
Should I replace head gaskets? Valve job?
The 420/420's are said to be low hour and run strong but I would do a compression test/leak down before install so lets assume that compression/leak down yeild good results.
Any more pointers?
From my research I will need to use my existing bellhousing, flex plate, and starter. I am fairly sure that my shift bracket will mount to the riser with a bracket and keep it in the same location. I also think my throttle cable should work with no modifications. Oil filter may have to remote mount.
What else am I over looking?
But before I did all this work above and take out a perfectly good 330hp motor what should I consider doing to the 22ish year old 420/425.
Should I replace head gaskets? Valve job?
The 420/420's are said to be low hour and run strong but I would do a compression test/leak down before install so lets assume that compression/leak down yeild good results.
Any more pointers?
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Would like to run 65. Then get hooked on speed and buy a faster boat...lol
I just can't not mess with something.
I just can't not mess with something.
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flywheels are different from 330 to 420, you need a flywheel from a forged crank not cast, they are balanced differently. I went from a 330 in oulaw24 to a new 435hp 502 this year and picked up 10mph...58 to 68mph....
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I am at 59 now with the 330 so 65 is real doable with 90 more hp. Just leary of a 22 yo motor. Dont want to invest 2500 to 3500 now on a pos old motor that needs 3k to 5k of rebuild work one year later.
LC
LC