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compression ratio '95 350 mag?

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Old 05-03-2007, 12:31 AM
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Question compression ratio '95 350 mag?

I have a '95 Scarab 29' with twin 350 mags. I purchased a service manual for this boat and found it has 250 hp not 300 hp. These are carbirated engines, with alpha 1 drives. I have decided to add small blowers, for altitude compensation. Not sure of compression ratio of these engines, it does not specify it in the service manual for this boat. Does anyone know the compression ratio for this year of 350 mag?
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Old 05-03-2007, 07:05 AM
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If they are 350 mags they should be 270. The only difference between the 260 and the 270 mag was the bowtie intakes. The mag mpi's are 300 hp. Do you have the weber carbs? Not sure of the ratio , someone will chime in. Let me know how you make out , I'm very interested in the results!
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Old 05-03-2007, 08:52 AM
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dont the mags have better internals? my 87 350 mags were the 270hp ones with alphas.
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Old 05-03-2007, 10:46 PM
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Not sure of the internals of Mags vs Non-Mag just learning about these motors myself. Not trying to argue with anybody but I have a Clymer MerCruiser shop manual which states that the '95 Mags are 250 hp and if Alpha's can handle 300 hp that is what I want to put to them. The carborators look like either Carters or Edelbrock but I am not sure. I would go look...but I don't want to drown in our rain storm. I need the compression ratio to know if I need lower compression pistons with the use of a blower. If anyone has any info I would appreciate any advice.
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Old 05-03-2007, 10:55 PM
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Alphas can hold up to 400hp with good reliability.
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Old 05-04-2007, 08:18 AM
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that should have dished cast pistons for about 9 to 1
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