Advice on 454 magnum paired with Alpha One

dpostman21

Seaman
Joined
Apr 20, 2016
Messages
53
I am looking at possibly purchasing a 1987 Sea ray Sundancer 268. I have done a little research on pairing, the 454 magnum and the Aplha one pairing seems to have mixed reviews. Understanding the Alpha One is not fully designed for the amount of torque/HP the 454 puts out and breaking shafts is a real possibility if driven recklessly. its my understanding that the Alpha One was rated for 300HP (not sure on the torque) and the 454 Magnum puts out 330HP.

My question is:
  • Is it all doom and gloom with this pairing?
  • Does the Alpha One hold up if properly maintained and driven correctly (Not mashing throttle from a stand still)?
  • Is this a pairing something I should steer clear of?
A little history on the boat. The boat is currently owned by a person who bought from the owner of a marine repair shop locally 4 years ago. The marine repair owner has serviced this boat for 20 years as he bought it from his customer who had him do the maintenance on the boat, put it in the water for him in the beginning of the season, and take it out at the end of the season servicing it along the way. I thought "well if a marine repair person wanted to by it after servicing it for 10 year it must be a decent boat."

My gut tells me this pairing is bad for a boater that does not understand the load they are putting on the out drive when dropping full throttle out of the hole instead of easing onto plan then increasing throttle.

Any and all thoughts are welcomed, I really appreciate the advice. I have pictures if that helps.
 

alldodge

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The 454 was rated 330 but during that time it was calculated and not actual HP at the flywheel. In any case there should be no issue with the alpha drives, if drive easy. Don't drop the hammer and they should be fine IMO. Now that said I would still take Bravo's over Alpha's Gen 1 because of not needing to split the drive tor replace the water pump. Might go Alpha Gen 2 because the impeller last longer between changes
 

dpostman21

Seaman
Joined
Apr 20, 2016
Messages
53
Thanks ALLDODGE!!! that makes sense and kind of confirms my thought. I fully understand this is not a speed boat and should be driven as such. Just looking to get my family on the water to enjoy some fishing and beach time. Not looking for a race LOL!!!
 

HT32BSX115

Supreme Mariner
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Dec 8, 2005
Messages
10,083
The 454 was rated 330 but during that time it was calculated and not actual HP at the flywheel.
My current 1987 Four Winns Liberator was available with an advertised 330hp 454/Alpha (although my brother bought it new with the 340hp OMG 460 King Kobra.....he HAD to have that additional 10hp:rolleyes::rolleyes:......go figure!!)

I installed a 1997 454 (NON-magnum, Carbureted) It's rated (by Merc) at 300 PROP-shaft HP. That certainly makes the crankshaft HP higher (and some estimate about 10% is lost in the drive) so it's somewhere around 330 crankshaft hp.

Now having said that, Mercruiser DID intentionally install the Alpha on the back of the 454 until the Bravo was available and some of them DID have problems...............But they didn't ALL break.

You'll be fine if you avoid "hammering" it (meaning WOT standing starts) like suggested above.

Just throttle it up smoothly, use your drive trim to help get you up on a plane and adjust it for maximum speed at a medium cruising RPM. The drive "angle" for hole-shot will not always be best for most efficient speed once up on plane.

You won't be running around at WOT very often when up on "plane" anyway. Fuel Flow at WOT is "spectacular" to be sure........you won't want to be there very often!

Congrats on your "new" boat!!:thumb:


Rick
 

dpostman21

Seaman
Joined
Apr 20, 2016
Messages
53
Thanks Rick!!! I am looking to cruise around with the family and likely fish off the back in Lake Huron/St. Clair River. I understand WOT = $$$ and heavy wear and tear. This is my first Sizable boat (currently have a 14ft Lonestar 1959) Have drove boats only up to 25ft (19ft Sea Ray & 25ft Baja Outlaw) Just plan on taking it slow (especially docking) this is not a speed boat that's for sure!!.

I really like the layout of the Sea Ray 268 best of both worlds for me cause I can take the 3 boys out and let them hang at the sand bar yet still fish :D
 

wrench 3

Commander
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Aug 12, 2012
Messages
2,108
I'm running a 1986 26' aft cabin with the original 454 magnum on an Alpha One. It had a rebuilt lower on it when I bought it about seven years ago that all ready had a banged up prop and a broken skeg. I rebuilt the upper two years ago for a broken tooth that I believe was from previous shock loading.
It's definitely a little light for the job but I believe they were more of a problem on ski boats rather than cruisers.
 

dpostman21

Seaman
Joined
Apr 20, 2016
Messages
53
No Title

I can get this boat for $8,500 is that a OK price?

1987 Sea Ray Sundancer 268
454 Alpha One (677 hours)
Triaxial trailer
20 amp charging system
Full camper and morning cover
Very clean.
 

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alldodge

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Good looking boat, if the stringers and transom are in good shape it would be a good price.
 

dpostman21

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Apr 20, 2016
Messages
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Was thinking on getting it surveyed as I would not know what to look for interms of the stringers and transom being good or bad. Figured if I got it surveyed I could find out the details on moisture in the hull. This boat has been maintained by our local marine repair for the the last 15+ years, fact is the owner of the marine repair shop boat the boat after servicing it for 10 years then a friend of a friend bought it from him so I figured its probably in great shape.
 

ottawamerc

Petty Officer 2nd Class
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Sep 16, 2004
Messages
128
I bought the exact same boat last year with a blown up Merc 260 /Alpha for $3700. Rebuilt the 260 ($3000) plus other stuff for another $700 so very near the price range of yours for a turn key. We love the boat but the 260 was way too small for such a heavy boat and I did not want to blow up the new Merc so I started research on putting in the 454, a fairly easy swap but everyone said the 454 would eat up the Alpha drive so I opted to install a Bravo too. There are some on the CSR forum that have your combo and they have had years of reliable service but all agree that smashing the throttle will kill the Alphas. I also changed the trim tabs on mine as those little 12X12 do nothing for it.
 

thumpar

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Jun 21, 2007
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6,138
One thing to keep in mind is that the ratio is a rare one so parts are hard to find if it does let go on ya. There are only a few that are ratio specific. If that were to happen you could swap to a Bravo setup or 1.5 drive and hope to prop it though.
 

wrench 3

Commander
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Aug 12, 2012
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2,108
One thing to keep in mind is that the ratio is a rare one so parts are hard to find if it does let go on ya. There are only a few that are ratio specific. If that were to happen you could swap to a Bravo setup or 1.5 drive and hope to prop it though.

As I said, I rebuilt mine two years back. Couldn't find aftermarket gears but the OEMs were no problem to get.
 

HT32BSX115

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Messages
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One thing to keep in mind is that the ratio is a rare one so parts are hard to find if it does let go on ya. There are only a few that are ratio specific. If that were to happen you could swap to a Bravo setup or 1.5 drive and hope to prop it though.
It would be an expensive swap to any Bravo, but the best choice for a boat that big would be a Bravo III.
 
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