Mercruiser stern drive OK?

I am considering a 1979 Mark Twain 24' cuddy cabin. It has a Mercruiser 260 and I have been doing some internet reading that makes me wonder what version I have. Can anyone tell me if this is an Alpha or an older version? I have always had outboards and this will be my first stern drive if it is a worthy project. I can use all the advice I can get as I don't want to buy a basket case.
Thanks so much!
Jeff

 

Hard to tell without a closer picture of the outdrive. Based on 1979, it would be pre-Alpha. . . aka 'R' outdrive. Alpha drive came out in 1984.

The engine would be based on the GM 5.7 (350 ci) block. If you can find some serial numbers for the engine and the outdrive, you can look up exactly what it is.

Here are some pictures of the 'R' outdrive that you can use to compare.








Keep in mind that you are buying a 40 year old engine/outdrive/boat . . . so expect to do some work. BTW - even in the lousy pictures, the outdrive does not look that great.

 

Thanks so much. That is good info. In ball park terms, what does it cost to replace the outdrive if that is needed? I saw a thread about replacing the older unit with an Alpha 1. Is that a possibility? Are the parts readily available or am I getting myself into a tough market?

Again, I appreciate all the answers. I love the lines on this boat, but don't want my heart to run away with my wallet.
Jeff

 

You can check on Mercuiserparts.com and see if there are a lot of parts available or 'NLA'. I think you may have some availability problems, but there is always the used market.

Check eBay for outdrive replacement availability. If you had to go new, expect to pay a couple thousand ($2,000 ish). Sterndrive Engineering Inc. (SEI) makes look-alike Mercruiser outdrives that are less $$$$.

 

I have a pre-alpha drive on my 1972 Sea Ray. Mine looked like @#$% when I got it, but I took it to a shop that works on these old engines and drives and after taking it apart they said it was fine just needed new seals and gaskets and a new impeller, and a paint job. that was in 2008 and its routine maintenance is being done as I write this. The parts are available through internet outlets, or if there is a Merc repair shop in your area they can get them. Sometimes takes a while. Mine doesn't have that big an engine ( a Merc 165 aka GM250, a 6 cylinder inline) but if Mercury matched the two then it should do fine. Putting an Alpha on would require adapters between the engine and the drive because the bolts wouldn't match up (I asked the same question)

Oh yeah, you can find a lot of these old pre-alpha drives on craigslist, at least out here in the PACNW.

 

Ike, thanks for the thoughtful response. I totally didn't see it until now. I've been working on replacing burned up wires as the previous owners son crossed the wires of the dual batteries and toasted everything. Will try starting the engine soon now that the weather is good. Then see about the drive. If it is ok, I may just get it in the water a time or 2 to see what else is wrong. I have to replace the deck and I think transom. Will see about stringers and aluminum fuel tank when I get into it.