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Sportfire engine transplant.

SmurfOnAGixxer

SmurfOnAGixxer

New member
I have an 86 Sportfire that I just picked up sunday after trading my 1985 Honda ATC 250R 3 wheeler. This boat was originally equipped with a 4.3 and omc/cobra outdrive (which both are still in the boat) the engine has a knock to it, so it has got to come out. I am not going to be putting this engine back in.

I would like to know what kind of HP this boat can handle, because I have a nice 350 I would like to put in it, probably @ the 325/350HP mark. The engine and drive will NOT exceed the 1000lbs capacity that the boat is rated to for drive.

What I would like to know, is there anything I should worry about when putting this kind of added power to this boat, any modifications that should be done.

Will the OMC/Cobra outdrive handle the added power?

If you need to know anymore details please let me know.

Thanks in advance!

BTW, I have yet to get a tape measure, but the title says this boat is a 19ft, but after researching on the internet, I could only come up with 17fts. Are there 19ft Sportfires?
 
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if It was mine, I'd try to find a nice 350 Mag Mercruiser and a good used Alpha gen II outdrive, then modify the transom to fit the new outdrive. The omc/cobra drive isn't all that wonderful.
 
The reason I would like to use this motor, is that I do not have to pay to get another, I am trying to keep this as cheap as possible. This is practically a brand new crate engine.
 
My 88 diplomat (18 ft) currently has a 383 smallblock in it that is pushing over 400 horsepower and over 400 ft pounds of torque... in front of a merc alpha drive (sei lower half). I'm sure if I rag on it or run it wide open for a long ways, I'l lunch the drive... we just got back from a day of wakeboarding and skiing on the river. fuel economy is fine, sits a little heavy in the back, but not bad, runs 70's wide open, feels a little "loose" right at the top when trimmed out, but overall is really stable and handles great so far with the bigger engine in it and will cruise all day at aobut 50 turning 3500 rpms. No issues with porpoising or chine walk, put trim tabs on it yesterday and today we could hold a plane down to 12 or 13 mph, and it made a huge difference in how well it rides in chop (maybe 1 1 1/2 foot) at higher speeds...

Just my experience... Hope this is helpful.
 
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