Mercruiser 7.4L V8 Bravo compatability with an Alpha One

STINGER23

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Nov 13, 2011
Messages
22
I have a big block in my go-fast boat....Mercruiser 7.4L V8 Bravo. The boat has an Alpha outdrive. I was told that the Alpha drive + my big block will not work well....and that the drive would "grenade" in no time.

Is it true that i can end up with a blown Alpha, because the power my big block puts out?



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Thanks!
 

Bondo

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Re: Mercruiser 7.4L V8 Bravo compatability with an Alpha One

Is it true that i can end up with a blown Alpha, because the power my big block puts out?

Ayuh,.... Absolutely,.... Count on it....

The Alpha drives are rated to 300hp,... yer motor is rated at 330hp...

Yer motor is also not the original,....
It came out of a hull with a Bravo drive, as Bravo is a drive tag, not related to motors...

pretty nasty lookin' too...

The Life of the drive is totally dependent on the actions of the Operator's righthand....
Be easy, it'll last quite awhile,...
Mash it, 'n All bets are off....
Launch it, 'n ya need another drive...
 

Friscoboater

Captain
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Jul 3, 2009
Messages
3,095
Re: Mercruiser 7.4L V8 Bravo compatability with an Alpha One

Yep, someone changed the drive out to the lesser Alpha at one point, or just bought a flame arrestor cover.
 

ENSIGN

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Re: Mercruiser 7.4L V8 Bravo compatability with an Alpha One

I would not try to see (how fast will it go ???)
 

dubs283

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Messages
5,339
Re: Mercruiser 7.4L V8 Bravo compatability with an Alpha One

are you sure you have an alpha drive??

its tough to tell from the photo and i don't see any wires going to a shift interrupt switch on the shift plate in the engine photo

someone would have to REALLY want to install an alpha behind that engine if the boat originally had a bravo - its a lot of different parts and work to do so

take some close up photos of the drive and STBD side manifold riser/shift plate assy then we will know what you are dealing with

IF you do actually have an alpha drive on your boat you do not have a "go fast"
 

Don S

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Re: Mercruiser 7.4L V8 Bravo compatability with an Alpha One

IF you do actually have an alpha drive on your boat you do not have a "go fast"

It would be a go fast for a couple of times :p
 

tpenfield

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Re: Mercruiser 7.4L V8 Bravo compatability with an Alpha One

It is borderline with that engine . . . some of the standard 454's had 330 hp, and later years they had 310 hp.

So, if you 'baby' it, then it may survive. If you do a fair amount of the GFBL thing, then have your Sea Tow membership up to date.

Don't tell any of your GFBL friends about this either, as they probably all have Bravo drives. :)
 

Bondo

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71,241
Re: Mercruiser 7.4L V8 Bravo compatability with an Alpha One

are you sure you have an alpha drive??

its tough to tell from the photo and i don't see any wires going to a shift interrupt switch on the shift plate in the engine photo

someone would have to REALLY want to install an alpha behind that engine if the boat originally had a bravo - its a lot of different parts and work to do so

take some close up photos of the drive and STBD side manifold riser/shift plate assy then we will know what you are dealing with

IF you do actually have an alpha drive on your boat you do not have a "go fast"

Ayuh,... It's an Alpha 1.... This is in his other thread,....



I have a 1984 Chris Craft Stinger with a Mercruiser Bravo 7.4L...its 454 cid...
Im looking for an engine manual and all the info to look up the engine online, but cannot find it.

Can anyone help?

All I know is:

Mercruiser
454 c.i.d
7.4L/V8 Bravo
Thunderbolt Igniton/Power steering

Thanks!

Sam

I'm thinkin' this boat started out with the 260hp/ Alpha 1....
Somebody's stuffed a BBC in it,.....
A pretty rough lookin' 1 at that....
 

O-fishal

Petty Officer 3rd Class
Joined
Nov 4, 2011
Messages
91
Re: Mercruiser 7.4L V8 Bravo compatability with an Alpha One

Wheres the skeg?
 

Don S

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Messages
62,321
Re: Mercruiser 7.4L V8 Bravo compatability with an Alpha One

Wheres the skeg?

Actually, the skeg hates to be away from the boat, and is camera shy. So when the drive is removed, the skeg is removed from the drive and placed just under the boat out of camera view ...........

Here's your sign. :facepalm:
 

O-fishal

Petty Officer 3rd Class
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Messages
91
Re: Mercruiser 7.4L V8 Bravo compatability with an Alpha One

HA HA:redface:
 

Thalasso

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Re: Mercruiser 7.4L V8 Bravo compatability with an Alpha One

Is that the fuel/water seperator lying on the floor.
 

Pete104

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Apr 30, 2011
Messages
1,439
Re: Mercruiser 7.4L V8 Bravo compatability with an Alpha One

She's a beauty!
 

MSFAB

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Feb 1, 2012
Messages
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Re: Mercruiser 7.4L V8 Bravo compatability with an Alpha One

I would say if you had a light weight boat then you would be fine but the stinger 23 is a heavy boat. i have a 87 baja 220 sport with a stock 330 454bbc and an alpha 1 drive and have had 0 issues with it and i beat the **** out of it 60mph+ on a regular basis but the boat only weighs in at 2200 pounds.
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
18,112
Re: Mercruiser 7.4L V8 Bravo compatability with an Alpha One

You can hook up a BB to an Alpha.You will need to re-gear the upper.It's a 1-32-1 or something like that.
It will work and work good.I wouldn't expect it to last forever as it really needs a Brovo or bigger.
Friend had a Donzi with twin 454's and Alpha drives and it worked great.Just install drive coolers.
It wasn't a race boat but got about 60.Jasper sells the reman upper and from the looks you need a lower case.
Just send it all to Jasper.J
 
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