Conversion and Restoration OMC Stringer to Whatever

RiverNoob

Cadet
Joined
Aug 11, 2015
Messages
27
I don't know if I will be able to find a complete donor boat setup, I will try, but just in case I can't by February or so,
I got a few questions to aid in my search:

1) Will all the marine parts from a 5.0 mercruiser fit on a 5.7 mercruiser?
2) A 5.0, or 5.7 mercruiser engine previously mated to a pre-alpha drive, should be able to be mated up with a new Alpha gen 2, with the correct coupler, bell housing, and transom assembly, correct?
3) The transom assembly for an Alpha gen 2 outdrive from a V-6 setup, should be the same as one from a V-8 setup, correct? It's only the outdrive and engine that is different, is it not?

Appreciate it, I asked these same questions to sterndrive.com and they don't seem to get back to ya very often,

Thanks,
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,464
Ayuh,..... #1, Yes, other than an Efi/ Mpi set-up, which the fuel map would be off,.....

#2, Sure, no real problem, but the 2 pc/ 1 pc rear main seal changes in '86,....

#3, Only problem there is the gear ratio change, the hard parts are the same, 'n fit the same....
 

RiverNoob

Cadet
Joined
Aug 11, 2015
Messages
27
ok,, so since that pre-alpha motor will go,

one strategy I can do would be to:

I can get a pre-alpha, older donor boat with a 5.7 for my engine and cables up to steering,, sell off the outdrive and extra parts and trailer,,
my brother is an auto mechanic and has all the tools to make it shine, and knows how, plus he has a fully rebuilt motor and I think an extra block already.
and then just get a transom assembly and outdrive to mate onto it.

I've seen older boats with decent condition 5.7's pre-alpha for 500-600, could prolly offer em 100 less at least, some might take 300.
I think I would rather have a 5.7 with a carb instead of fuel injection anyway

Then I just need to change out this rear main seal,, and the motor portion is good, right bondo?

So then I need a transom assembly either from a 5.7, or one from a v-6 or other V-8, and an outdrive with the 1.47 gear ratio, I believe that is the gear ratio for V-8 outdrive-------
Just one thing,, with the gear ratio,, I had thought that was only in the outdrive itself,, with the drive-shaft,, The transom assembly that bolts on with the plate and rams is all the same correct?

So I have seen a number of donor boats with this motor I think I can get one for 400, put a couple hundred into fixing the motor up lets say. I won't count any refunds from parts sales.
So 600 motor and pulleys up to console,
900 for used outdrive with transom assembly, seen a couple of those recently for about that price

may need to also get a separate bell housing, and this rear seal, bout 1800-2000 for the whole motor setup,
plus costs for the marine plywood, other wood, fiberglass and epoxy.

That sound about right to you?
Are there important things missing from this plan?
 

RiverNoob

Cadet
Joined
Aug 11, 2015
Messages
27
I have a new question now,
I found a donor boat for a good price, but it has a 4.3L Mercruiser V-6 engine.
Do you guys think that would be adequate for this type of boat? It's over 24 ft, and pretty heavy, but it also has the deep vee that should cut through the water and chop pretty well.
If I outfit the 4.3 with a 4bbl, I think you can usually make them a 205 hp setup.

Or do you think I need to stick with the 5.7L plan with more push?
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
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Jul 23, 2011
Messages
47,296
thats a big boat. I would stick with a 5.7
 

RiverNoob

Cadet
Joined
Aug 11, 2015
Messages
27
Hey iboaters, I'm still on this project though its taking far longer than I ever thought,
so far I just have the boat gutted and have gotten the proper tools together, and been watching lots of transom rebuild videos,

I'm having trouble finding a donor boat, or a setup for the price I want,

I just ran into a guy selling a Volvo 270, and it has all the transom assembly, controls, and all the marine motor parts with it, (except the actual motor was blown, so I would just have to get a new block and put it back together)

This 270 was previously on a 350, so gearing is correct.

Is this a good option to go here you guys think? or should I stick with trying to put together a mercruiser alpha gen II setup?

Also when I was gutting my boat, it became obvious that my transom is not flat, like most of the videos I have seen with rebuilds. The transom on this boat is actually 3 sides with 2 angles as you can see in the pictures. Is that going to be a big problem? I was thinking it shouldn't be if I attach stringers where the old ones were to the corners of the middle flat section where the outdrive would be.

also let me know if I need to start a new thread since my post is kinda old, I don't know the rules on that.

Thanks,
 

Rick Stephens

Admiral
Joined
Aug 13, 2013
Messages
6,118
Nothing wrong with a good VP. Stay with some horsepower. V6 will be on the light end.
 
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RiverNoob

Cadet
Joined
Aug 11, 2015
Messages
27
ok, well there also seems to be a good amount of parts and used drives for Volvo 270-290 around, and this guy can sell me everything but the block on the cheap.
So I think I'm going that route.

Does anyone have any pointers/tips/observations about the transom shape in this boat?
 

Woodonglass

Supreme Mariner
Joined
Dec 29, 2009
Messages
25,924
No need to start a new thread. Transom build should be done just like it was before. If you switch to the VP motor make sure you understand the Transom specs and motor mount/alignment reqs. needed for the swap.
 
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