350 Mag (5.7L) and Alpha One 1.84???

boatwop

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Aug 24, 2015
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2
Hi All,

I have a 1995 Blue Water Monte Carlo (20') with a 350 Mag and A1G2. We've owned the boat for 3 summers now and have loved every minute of it. It has been a great boat and extremely reliable. Runs like a top. Aside from annual maintenance we've never had to touch it. I've been experimenting with props and just last night noticed that the ratio on my outdrive is 1.84. If I'm not mistaken, this was the norm for the 4.3L in this era, but nowhere near the norm for the 350 Mag. I don't even think the 1.84 was recommended for High Altitude applications with this engine. I compared S/N's to the info tag on the cowling of the motor. It looks to me like everything is factory. The S/N for the outdrive is worn off the cowling on the top of the engine so I can't read it 100% but from everything I can make out I'm pretty sure the outdrive S/N matches as well. So my questions is......... can anybody make any sense of this? The boat is fairly heavy but it hauls serious a** with this setup. I know that the boat was available from the factory with the 4.3, 5.0 and 5.7. I was trying out a 23" 3 Blade SS prop. With a full tank of fuel and a ton of gear I could hit the rev limiter with ease and still had a good amount of throttle left to play with. I was surprised that this boat was capable of spinning such a high pitched prop which is what brought me to confirming the outdrive ratio in the first place. I've figured out where I need to be for props so that's not what I'm here to rant about. I'm more curious as to whether or not anybody else has come across this ratio on a 350 Mag as a factory setup before. Should I be worried at all? I understand what this means in regards to prop pitch. Are there any other issues one should be worried about? Like I mentioned earlier, I've had no issues with this boat which is why it has taken me so long to discover this. I've spent a lot of time around high performance boats with outboards, but am rather ignorant when it comes to I/O outdrives. My wife wouldn't let me buy the Skater 24 w/ Twin 2.5L Diamond Builds that I really wanted, so this is the boat we ended up with to get our new family into boating.

Thanks in advance for all responses.
 

thumpar

Admiral
Joined
Jun 21, 2007
Messages
6,138
I don't know that the 1.84 was an option on the 350 mag. I know the 1.62 was on the 5.0l and maybe on the 5.7l (not sure about that). The drive is most likely not original. With a 350 mag you are at the rated limit of the drive anyway.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Jul 23, 2011
Messages
47,296
welcome aboard

I would verify the ratio by puting a piece of tape on the crank pulley, one on the prop. have someone watch the prop while you rotate the motor with the starter after you disable the ignition. could simply be the wrong sticker on the drive, or someone could have swapped out a 5.7 for the 4.3
 

JASinIL2006

Vice Admiral
Joined
Feb 10, 2012
Messages
5,524
My 350 Mag has the 1.47 ratio. I thought that (or 1.50) were pretty common for that engine.
 

boatwop

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Joined
Aug 24, 2015
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If memory serves me correctly, the 350 Mag came standard with the 1.47 A1G2 which later became a 1.5. I do know that this is the original engine that came with the boat. Pretty sure the outdrive is as well, but could be wrong. I feel like the decal on the outdrive is correct as I can run a 24" prop on this boat and be right at the top of my Max Operating Range (4800 RPM). I guess at the end of the day I likely don't have anything to worry about as long as I'm running the right sized props and not over revving the engine. It works really well. And when I throw the Hi-Five on, it pulls all 225lbs of me out the water on the slalom (double suicide boots) no problem.
 

thumpar

Admiral
Joined
Jun 21, 2007
Messages
6,138
They also came with Bravo drives. Mostly depending on who the boat builder was. Even if it was a high altitude boat it would have been a 1.62. The 1.84 is meant for the 4.3l.
 

flipbro

Master Chief Petty Officer
Joined
Feb 8, 2013
Messages
830
Try what Scott mentioned. It's possible its a rebuilt leg with 1.50 gears and the housing that had 1.84 originally.
 
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