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cruzman

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Friend has 87 27ft searay w/ 5.0 raw water cooled w/alpha drive.He wants to replace the alpha w/ a bravo 3. Not so sure this can be done without changing the transum plate and a LOT of grunt work. Any thoughts?
 
You are correct! He is in a pickle.
27 foot boat, with a 5.0L, and an Alpha drive.... not a good combination for power/speed in a 27 footer, IMO.

The A drive is at it's limit at 300 hp, and at what some say, is at 26-27 foot.
The BIII will not help much at speeds the engine is capable of in this hull. The BIII begins to perform at speeds above 40-45 mph, from what you can read.
A Volvo Penta Duo Prop would serve him much better, if staying with the 5.0L. (prop design is quite different, and is more effective at these speeds)

He's got a few decisions to make!
.
 
cruzman said:
I actually thought it would be easier and less expensive to repower and reprop. Keeping the same drive on the boat.
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You can verify this, but you'll find that the A drive is at, or is near exceeding it's limit at 26 foot.
Add more hp/torque, and now it's capability is being exceded in two aspects.
Is it worth it?

I have changed several A drives to the V/P Duo Prop, and I have changed many V/P single prop drives to the Duo Prop.... always with excellent, and beyond expectation results.
It's all in the prop design that others cannot yet use.
 
cruzman said:
Friend has 87 27ft searay w/ 5.0 raw water cooled w/alpha drive.He wants to replace the alpha w/ a bravo 3. Not so sure this can be done without changing the transum plate and a LOT of grunt work. Any thoughts?
Click to expand...

Ayuh,.... To do that, he needs to replace Everything, from the pulleys to the prop...
 
Depends on what your friend wants ???

A few options even though you didn't as.

Change the drive. Still won't get any more out of the boat.

Change the motor to say a 350 he will only ger 5-10 mph. Keep the drive.

I don't think the 350 has enough Mojo to move that boat where he wants it.

7.4 set up right might just be the ticket, with a bravo or volvo. Big money new, and you still have a old boat and the sinking of that many greenbacks into it might not be the way to go.

Vovlo right now has a chit load of quality issues. Don't get your panties in a twist Rick, just saying.

Only way i would do it is with a donor boat bad hull with the power and drive package you want. This way you don't killed on the small stuff, just pull what you got sell it and offset the stuff off the donor.

Or you can get rid of that scow and buy the package you want with the hull you want it in.

Tell you the truth that 5.0 and drive i would not install over 23 ' And in a 21' would be perfect.

Really depends on what the owner want to do. How fast is he going now ?
 
a 502 HO and a bravo II, that boat will pop out of the water and most likley run at or above 50 mph

or call Reggie Fountain of Foutain Boats in Florida and ask him what to do.............


WHat he has there is equivilant to a row boat being rowed by a chipmunk..........
 
How many bucks for that 502 and bravo ?

With gas going thru the roof thank g-d i got my 19' with the 140 hp. 8 gallons all day.
 
Thanks for all the replies. I don't think the boat is worth the trouble. Maybe he should look at a different prop and leave it at that.
 
cruzman said:
Thanks for all the replies. I don't think the boat is worth the trouble. Maybe he should look at a different prop and leave it at that.
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Cruzman, we cannot arbitrarily change props without considering WOT RPM as per OEM specs........ Wish it was that simple.

IMO, and since these are opinions only.... this boat does not necessarily need an almost 300# heavier BB in it. You can gain just about as much with a good 5.7L or a 6.2L SBC, and the DP.
The donor boat is a great idea. Find one that has been damaged. My friend who owns a marine salvage yard, picks these up all the time.

If he wished to go the extra measure, he custom build a 5.7L or a 6.2L SBC using a q/e combustion chamber design. This makes a much better suited SBC Marine Engine anyway.

Of course it's always so easy to spend someone else's money, isn't it? :D


Chief, as for the V/P issues, yes, V/P did and does have an issue with the composite drives. I did not, and would not recommend the composite drive. For those who know me, my preference would be to stay with an AQ series DP drive.... but that's another story, for another day.
 
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