Outdrive identification and swap.

[bishop1976]

I bought a 1991 wellcraft with a Mercruiser 5.7 magnum and the outdrive is heavily corroded. It looks like it may be serviceable and isnt leaking anywhere but I am on the lookout for anoher housing. I can't ID the lower unit because all the markings have been corroded or are painted over with black spray paint.

I found a 1991 chapparal that has a 305 and what is believed to be a Mercruiser Alpha I Gen II for a resonable price locally.

Will an outdrive from a 305 swap to a 350? Also how might I be able to identify my outdrive?

 

[Don S]

Re: Outdrive identification and swap.

The 5.0 and the 5.7 use the same gear ratio.
BUT, is the drive on the Wellcraft an Alpha I Gen II. That is the determining factor. Since it's a 91, it could be an Alpha I, and Alpha I Gen II, or one of the Bravo drives.

Only you know for sure.

Serial Numbers, then pictures , are the best way to ID what drive you have.

 

[bishop1976]

Re: Outdrive identification and swap.

Here are the pics of the unit I have and the unit I think is the same. YOu can tell which one is mine...the one that looks like it was at the bottom of the sea!

 

[Bondo]

Re: Outdrive identification and swap.

Ayuh,...

The dirty1 is an Alpha 1,...
The shiney1 is a Gen, II...

Brand new aftermarket outdrives are about $1400....
Why bone out a perfectly Good boat for just it's Drive,..??

 

[bishop1976]

Re: Outdrive identification and swap.

The floor is rotten to the hull on the donor boat. I'll probably part the whole thing out. I also need the gimbal housing etc.

So will the GEN I swap out with the Gen II? I'll be using the upper, lower, and gimbal housing. Will they all swap out?

 

[Bondo]

Re: Outdrive identification and swap.

Ayuh,...

As long as you're going all the way to the rear motor mounts,...
Ya,.. That's a straight up Swap....

You'll just have to drill 2 more holes though the transom, for the extra studs at the top of the assembley....

 

[bishop1976]

Re: Outdrive identification and swap.

I hate to dig up this old thread but I think I found a new lower unit. My dad cut this out of a boat with rotten stringers. The motor is a 470 and the lower unit appears to me to be an Alpha I Mecruiser. It is in very good shape. I know it isn't geared right for the Mercruiser 350 Magnum but I should be able to pull it, regear it, install it, and have a good running boat. Can any of you tell from the pictures if these outdrives will swap out? How much labor is involved in re-gearing the new lower unit?

Keep in mind I'll have to swap out everythingthing from the transom outward. That includes gimble housing, trim cylinders, etc. Whts on the boat now is corroded badly.

 

[bishop1976]

Re: Outdrive identification and swap.

a few more.......

 

[Bondo]

Re: Outdrive identification and swap.

Ayuh,... That 1 is an Alpha 1,... It'll swap, No problem...

Gears are between $300.to $500 for a set..... Plus labor to install...

 

[bishop1976]

Re: Outdrive identification and swap.

Can't I just swap the gears from one to the other? The drive on the boat is good it's just corroded to hell. I was going to swap housings. As nice as the donor drive is I may be able to sell or swap it for one that I can just bolt up.

 

[Bondo]

Re: Outdrive identification and swap.

Can't I just swap the gears from one to the other? The drive on the boat is good it's just corroded to hell.

Ayuh,... OK,... Then the Labor for the upper rebuild/ regear,+ the Seal Kit...

 

[bishop1976]

Re: Outdrive identification and swap.

What gear Ratio will I need for a 350?

 

[krisnowicki]

Re: Outdrive identification and swap.

1.5