Replacing Your Mercruiser 3.7L 470 Inboard Engine
Matt,
Question: What’s the best direction to go when replacing the old Mercruiser 3.7L/470 engine?
Unfortunately there is no single good option for this looking at a complete re-power. The 470 engine was an engine developed by Mercury Marine specifically for it’s purpose; to power boats. The inline configuration allowed for easy draining, a single intake/exhaust manifold was cheaper than two, etc. The engine was also a large displacement engine for its size and therefore made a tremendous amount of torque because of the stroke and displacement. On top of this Mercury utilized their die casting expertise to produce a light weight aluminum block and combination with the existing Ford cast iron 460 cylinder head.
To go up in Hp you will have to go with the typical V-Configured 350 engine which will also require a different drive ratio and propeller. With any changeover to the V engine configuration be it V6 or V8 this will also require completely rebuilding the stringer system in your boat. Many customers ask about replacing the 470 engine with the current 3.0L engine since they are also are an inline configuration. The problem with this is that the 3.0L makes approximately 135 Hp & 180 Lb-Ft of torque where the 470 made 190 Hp and approximately 275 Lb-Ft of torque. The 3.0L engine is simply too small and does not make enough torque
Check out the link below for the tech article that addresses this very subject
Regards
Performance Product Technologies/IShopBoating
8002 West 6th Street
Stillwater, OK 74074
(405) 533-3812
Fax (775) 257-1769
[email protected]
www.perfprotech.com
matt writes:
hi,
i currently have a 25 bertram with 2 x merc 170 which are dead…
i would like to replace with new complete engines?
would it be worth installing one engine or should i install 2 new engines?
what engine options would you sugggest?
also will you ship to Australia?
thank you matt