Volvo and a big block question

f_inscreenname

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Did any of the old Volvos (like the 270 / 280) ever come with a big block? Its winter and just through a rod in the small block. Its project time.
 

Don S

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Re: Volvo and a big block question

Nope. We have a boat we work on that put a big block in place of a 350 on the 280 drive that was upgraded to the DP. The problem is that mechanical lockdown can't hold it down and the drive will kick up, when that happens it pokes a hole in the bellows, since we are in salt water, it kills the ujoints and the intermediate bearings in the engine bellhousing.
Have pulled the engine 3 times this year for the same thing, and yes everything is adjusted perfectly, and all new, including the transom shield and drive intermediate housing.
 

f_inscreenname

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Re: Volvo and a big block question

Well part of my past spring project was installing a 280T transom shield with the works. Don't have to worry about that over priced hook to much (I had to replace one before). I take it you all believe that the outdrive will hold up? What did you all use to mate the big block to the small block bellhousing?
 

Don S

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Re: Volvo and a big block question

I think you will find you still have that expensive hook, even with the trim.
 

Reel Poor

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Re: Volvo and a big block question

Don said:
The problem is that mechanical lockdown can't hold it down and the drive will kick up

Whats causing the drive to kick up? Is he over powering the locking device while reversing? Surely the drive isn't kicking up while in forward.

What size boat and motor is this?

BTW...What kind of power will the 280 drive handel?

 

Don S

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Re: Volvo and a big block question

The "Kick up" I was talking about is when the drive is put into reverse. Between the 454 torque and the Dp conversion, it's just too much for the lockdown mechanism.
I have no idea if the lockdown will hold when just using a 454 with the single prop, I know they used the 280 (Single prop) with the 40 series dieslels (6 cylinder 160hp) so it may be that the DP conversion along with the higher idle speed of the 454 (700-750rpm compared to 600 to 650 for the diesel) might be the problem with the lockdown.
As far as the insides of the drives go, they are fine with a big block.
 

f_inscreenname

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Re: Volvo and a big block question

Don said:
I think you will find you still have that expensive hook, even with the trim.

Ya but since it doesn't have to disengage any more for up and down, if it broke I could fix it forever if needed.
 

Reel Poor

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Re: Volvo and a big block question

Thanks Don......Your statement just raised my curiosity.
 

f_inscreenname

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Re: Volvo and a big block question

Don said:
As far as the insides of the drives go, they are fine with a big block.

You just gave me the best news I've had all weekend. Did you use a kit to mate the bellhousing and motor together or was it home made?
 

Don S

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Re: Volvo and a big block question

We didn't make the conversion, and there is no "Kit" but you can find a bellhousing for the engine from either an MD or NC model 7.4 that used the 290 style drives.
They used the newer style Volvo manifold also, not the old D style manifolds and risers. Plus some other elbows and exhaust hoses to mate up with the exhaust Y on the boat. Knowing you, you will be going thru the transom which will be a lot less heat in the drive and better for performance.
 

f_inscreenname

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Re: Volvo and a big block question

Don said:
Knowing you, you will be going thru the transom which will be a lot less heat in the drive and better for performance.

Already have that now. Over the weekend on my last ride of the season I through a rod in my 320hp/360ci mopar. I am sure it has something to do with me pushing the throttle to far to many times. But it is a big heavy boat and it takes some pony's to push it around. Looking to bring the rpm's down by bringing the power up. Not only that but I have the 360 about wound out now. If I can pop up the HP a ton and still keep the compression to 8.5 to 1 I will be on the right path.
 

f_inscreenname

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Re: Volvo and a big block question

Oh and No more mopar. Way to much money and parts are to hard to find. Going the cheep and reliable road this time, Chevy 454 I hope.
 

Bondo

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Re: Volvo and a big block question

Going Chevy will Cure the Bellhousing Problem,............

Their All the Same................

Sounds like a Fun Project.............:love:
 

f_inscreenname

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Re: Volvo and a big block question

bond-o said:
Going Chevy will Cure the Bellhousing Problem,............

Their All the Same................

Sounds like a Fun Project.............:love:

All Chevy (big and small) are the same bellhousing? God I hope so. I have about everything else. Still need a bare motor but that is the least of my worries.
 

Bondo

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Re: Volvo and a big block question

Ayuh,.........

From the 2.5l to the 7.4l,.......Same Holes.........

The Big Blocks do have 1 Extra hole, Top Center,.... But you won't miss it.......
 
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