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Changing 4.3 to 350 89 searay cuddy

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backyardal

New member
New here want to change 4.3 to 350 engine the motor supports is what im trying to find about do i have to move them on the boat or do they sell a kit or something any info.
 
Depends on the hull and where the V8 mounts will sit. Might be enough stringer to just redrill and lag or new mounts will need to be glassed in
 
I do not believe there is a kit.

Too many different boat manufacturers boat building methods....

The 4.3 and the 5.7 are in essence the same block so to speak and the 4.3 is 2 cylinders less (shorter).

So the only thing needed is to relocate the stringer motor mount where it mounts to the stringer. Typically two large lag bolts.

The engine motor mounts appear to be exactly the same part number so they can be reused on the 5.7
 
The standard, non injected MERC 5.7L is rated @ 260HP and has heads and cam designed for marine use. The FI injected versions of this engine all are rated @ over 300HP. How many HP are you looking to put on this hull? I've used one of these on a re-engine of my 4000# ChrisCraft deepV cuddy. It does 40 MPH @ WOT and cruises quite nicely at almost 30 mpg.

Generally not a good idea to apply "street" cams and heads to a non marine engine to convert it to a marine application, or to a base marine engine for that matter. MERC (and the other top tier marine engine providers) have done a good job of getting a good balance between HP out and longevity. Ricardo has some expert views on piston/head issues... Stay tuned!
 
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