Really need your help with 350 mag replacement engine??
#1
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Really need your help with 350 mag replacement engine??
I've read a lot of posts on engines and I'm just have trouble coming up with a plan for this boat...
I bought a 1989 Glastron CSS-19 and I turned it into a project boat, not by choice, it's just started with a soft spot on the floor and then some cracked exhaust manifolds, then I take the interior out to get it redone and decided to pull the motor to give more room in the stern to work... sooo since the motor is out What the hell, why not put a fresh engine in.
The boat has a 350 Mag that says that it is a 270HP motor. This boat stock is said to have a speed of between 60-65mph and I have never had a boat that goes this fast, would it be unsafe to put a new engine in that has 300-350 HP?
And my main question is, dollar for dollar what is the most bang for the buck in replacement engines that are out there. I have skills do do the work myself as far as taking an engine a part and replace cams or heads so I could really use some good advice on an engine. I don't need to be the fasted boat on the water, nor spend the bank on a motor, would like one that would run a long time, but have a little more spped then stock.
Would this be some kind of crate motor or...??
Thanks very much for your advice,
Dan
I bought a 1989 Glastron CSS-19 and I turned it into a project boat, not by choice, it's just started with a soft spot on the floor and then some cracked exhaust manifolds, then I take the interior out to get it redone and decided to pull the motor to give more room in the stern to work... sooo since the motor is out What the hell, why not put a fresh engine in.
The boat has a 350 Mag that says that it is a 270HP motor. This boat stock is said to have a speed of between 60-65mph and I have never had a boat that goes this fast, would it be unsafe to put a new engine in that has 300-350 HP?
And my main question is, dollar for dollar what is the most bang for the buck in replacement engines that are out there. I have skills do do the work myself as far as taking an engine a part and replace cams or heads so I could really use some good advice on an engine. I don't need to be the fasted boat on the water, nor spend the bank on a motor, would like one that would run a long time, but have a little more spped then stock.
Would this be some kind of crate motor or...??
Thanks very much for your advice,
Dan
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Merc long block. Stay away from the crate engines as you will be dissapointed. Been there done that. Long block from merc will run you around 3200 with a 2 year warranty.
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Write Glastron, and ask them. I did the same when I was looking at a 1980 Glastron Carlson CV-27. It still has the original inline 6, I wrote Glastron and they said the best ballance size/hp would be 305's.
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The boat came with a 350 mag that is stock, and going to a 305 would be less power then I have now. There is such a debate over the Chevy crate motor at about $1600 and the Merc at $3200. From what I've read that the head gasket are SS and the freeze plugs are brass are the two main differences between the two, oh and the cam profile. The boat has the Alpha One. I also bought a set of the Alum GLM exhaust manifolds. Still would like to get a new motor at the best price, but which one?
Last edited by zgoo; 05-02-2007 at 05:25 PM.
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These guys that sell you a crate engines lie. For example , offered for sale at a "marine repower center" are gm long block base motors , 350 275 hp , 4 bolt mains , roller cam. Sounds good right? That motor will have less hp than the merc 305! Warranty , yeah right , good luck there. If you can get a build sheet ( you never will ) and see that the correct marine cam is in it and the right size and material valves, I might for a minute think about it. Then I'd wake up! Do it once and do it right , believe me , been there with twins. The gm crate motors will not make the power the mercs do. If you want to go through the motor and do the mods you may end up with a nice package but you will have more in it than doing a merc block. Buy the crate and your headaches will begin from little things like the timing cover will not fit under the circulating pump to the final test run and you find you'll have to drop 2" in prop pitch to get the pos to wind up in rpm and probably lose 6-8 mph in speed. Mild Thunder has a better idea than a crate.
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I would have reputable marine shop build you a nice shortblock and then you can add your choice of heads, cam, valvetrain etc... I went this route over the winter.
1980-85 4 bolt block, forged internals, balanced, 10.0-1 SCR, AFR 190cc heads, XM276HR cam, Performer RPM, 4150 750CFM, HP exhaust manifolds. I am very happy with the performance and way it turned out. It made 426hp on the dyno with dyno headers. I figure in the boat with the manifolds it will be around 400.
1980-85 4 bolt block, forged internals, balanced, 10.0-1 SCR, AFR 190cc heads, XM276HR cam, Performer RPM, 4150 750CFM, HP exhaust manifolds. I am very happy with the performance and way it turned out. It made 426hp on the dyno with dyno headers. I figure in the boat with the manifolds it will be around 400.
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Turn your 350 mag into a 383 you can get 425 hp out of it on pump gas 9.3 comp. prices have come way down on the cranks and you can get a good set of rod for under $ 300.00