What is 454 Alpha 1 gear ratio?

[Silly Seville]

Hey Guys,

I know the 350/260 Alpha 1 is 1.50:1

Did the factory installed ('87 & '88) 454/330 Alpha 1's use the same gear ratio?

If not, can I use one behind a 320 hp 350 without undue stress or harm? This is on my express cruiser.

Thanks!

 

[Bondo]

Re: What is 454 Alpha 1 gear ratio?

Ayuh,... The BBC used a 1.32:1 ratio...

When ya get over 300hp, it don't matter what ratio ya run, as the Alpha drives are in the "Could Blow at any time" area...
The drive is rated at 300hp.... regardless the ratio...

Many guys are runnin' over 300hp, but the operator's throttle hand is the only thing between runnin' reliably, 'n a Blown drive...

 

[Silly Seville]

Re: What is 454 Alpha 1 gear ratio?

Thanks Bond-o! I am easy on the controls as I have no reason to shred gears and shed tears. I know that the 454 is a torque monster...is that the reason for the different ratio? Or is it more related to total horsepower as you mentioned, or RPM? The reason I ask is this. My outdrive is shot from years of electrolysis and I'm on the hunt for a good used one. A feller down the road is junking a similar cruiser with a good 454/A1 in it. Will running that 1.32 ratio make the boat perform differently than it did with standard gears? Will a prop change be in order? (currently using a 15P) And I should add that my 320hp is an educated guesstimate. Engine is slated to be a carbed 350 Vortec full roller with a 383 cam. Thanks again!

 

[Bondo]

Re: What is 454 Alpha 1 gear ratio?

Will a prop change be in order? (currently using a 15P)

Ayuh,... The gear ratio difference is 'bout the same as 6"s of prop pitch, 'n last I knew, you've already got the smallest pitch commonly available....

Personally,...
I'd go to a 1.65:1 ratio, 'n get back up into the middle of the commonly available prop pitches...
Must be a big heavy hull ya got...

 

[TilliamWe]

Re: What is 454 Alpha 1 gear ratio?

... I know that the 454 is a torque monster...is that the reason for the different ratio?...

The "reason" that I have read is that it makes one of the gears physically bigger and better able to withstand the power better. Not sure which gear, I can never keep that stuff straight in my head in regards to gear ratios and the which gear gets bigger or smaller!

I am with Bond-o, don't get a 1.32 ratio, if you are already using a 15 pitch prop behind a 350. Even with a power increase of what you are describing in your 350, stay with a 1.5 ratio or even a 1.65 like Bond-o says. That will allow you to use your 15 or maybe a 17 or maybe a 19 pitch prop, and there are TONS of them out there to choose from.
Regarding used drives, why not just buy an SEI Alpha One replacement drive? Alpha One is $1400 and they are brand new with 3 year no-fault warranties. Seems like a no brainer to me, especially if you're already spending money on the engine.

 

[Silly Seville]

Re: What is 454 Alpha 1 gear ratio?

Thanks for that info!

Yes Sir...with 100 gallons of fuel, 40 gallons of water and 3 batteries on-board, she is a fat girl...5700 lbs. Wish she was born with a 454!

 

[Don S]

Re: What is 454 Alpha 1 gear ratio?

Yes, Merc used the 454 with the Alpha from 86 to 88 then they came out with the Bravo.

Are you saying you now have an approximately 320 hp 350 and can swing only a 15" prop with a 1.50:1 ratio? If so, you have engine problems or something else wrong, and playiing with gear ratios isn't finding that problem just masking the real problem.

 

[Silly Seville]

Re: What is 454 Alpha 1 gear ratio?

...why not just buy an SEI Alpha One replacement drive? Alpha One is $1400 and they are brand new with 3 year no-fault warranties.

Hi Tilliam, I had considered a new SEI as I've heard very good things about the product and company, but after speaking with a fellow member of iboats about it, he opined that a true Merc drive, even used, was better than a new SEI. Again, that was his opinion, but I have a great deal of respect for his knowledge and experience, so I am lending his thoughts some credence. I am more than happy to entertain others opinions in this thread about the pros/cons of a good used Merc vs. a new SEI.

BTW Tilliam, greetings from a former Land 'O Lincoln resident. My misspent youth was stomping around Creve Coeur and Bartonville. Dated a girl at Richwoods High. Ahh, bittersweet memories and the stench of ADM still lingers in my mind! :facepalm:

 

[Silly Seville]

Re: What is 454 Alpha 1 gear ratio?

Are you saying you now have an approximately 320 hp 350 and can swing only a 15" prop with a 1.50:1 ratio? If so, you have engine problems or something else wrong, and playiing with gear ratios isn't finding that problem just masking the real problem.

Hi Don. No, I am currently building up a 350 Vortec to be stronger than the factory rated 260hp flat tappet 350 for the sake of reduced planing rpm's, and hopefully a longer service life. Since my drive is already barnacle chewed and corroded to a crispy critter, I thought now was an excellent time to review my cruising rpm options. A Sea Ray service department goon (err, I mean nice fellow) told me NO to even a 17P on the stock 350. Said I'm too heavy and engine will struggle for rated WOT. My goal is maximum cruise speed at the lowest rpm for greatest powertrain longevity. I had initially wanted to build a 383 stroker, but finances prohibit that. And a full blown 454/Bravo 1 swap is out of the question on this old tub. I could buy another cruiser cheaper I think!

 

[Don S]

Re: What is 454 Alpha 1 gear ratio?

At 5700 lbs, is a 350 is a bit on the light side. I was typing at the same time you posted the weight and didn't see that before my comments. I would be worried about going to a 1.65 ratio before trying the 1.50 with the new motor.
Do you have trim tabs to help lift the stern?

 

[Silly Seville]

Re: What is 454 Alpha 1 gear ratio?

Trim tabs most definitely! Wouldn't own a boat this top heavy without 'em!

 

[HT32BSX115]

Re: What is 454 Alpha 1 gear ratio?

There are deals out there in radio land!

I bought a complete waterpump-prop 1997 454/Bravo III (122hrs) out of a damaged boat in 2006 for $5000.

Then over a several year period, I sold all the OMG 460 KingCobra "stuff" for nearly $3500.

You won't have as much usable stuff to sell but you could recover more than you think...... Just an alternative.......

I don't think I would put an Alpha behind a 454 unless it was an SEI (with the warranty) but I don't know how many times they'll replace a broken one knowing it's going behind a BBC.

 

[TilliamWe]

Re: What is 454 Alpha 1 gear ratio?

...greetings from a former Land 'O Lincoln resident. My misspent youth was stomping around Creve Coeur and Bartonville. Dated a girl at Richwoods High. Ahh, bittersweet memories and the stench of ADM still lingers in my mind! :facepalm:

I know you are for real, you spelled Creve Coeur correctly! I think the ADM plant smells nice, as I drive over the Cedar Street Bridge every night.

I don't want to start a fight between you and a trusted resource, but there is no way in heck I'd buy a used drive instead of a brand new SEI drive. Too many variables with used, none with an SEI. Unless the used drive was free. But how many of them are?