Replacement engine weight vs. power

[jklnhyde]

I just bought a sweet 1976 Wellcraft Nova 25 that originally had a Merc big block and a Bravo 3 setup. The engine and out drive are the only things gone and the entire transom assembly is still there. I know this is a big, heavy boat, but I'm no racer and all I want is enough power to move the boat efficiently, so I need suggestions on what light, reliable and inexpensive I/O set up would be a good choice for me to consider. More than likely I'll be buying used or remanufactured, so that's an issue.
Should I stay with the Bravo 3?
I love the lines of this boat so a transom bracket/outboard conversion is out of the question, unless someone can convince me otherwise.

Thanx!

 

[TilliamWe]

Re: Replacement engine weight vs. power

I just bought a sweet 1976 Wellcraft Nova 25 that originally had a Merc big block and a Bravo 3 setup...

It may have had a B3 in it prior to you buying it, but I can assure you it did not Originally have a Bravo drive, as they weren't introduced until about 12 years after your 1976 model boat was made!

 

[Don S]

Re: Replacement engine weight vs. power

Stick with what you have.

I need suggestions on what light, reliable and inexpensive I/O

At BEST, you will only get one out of the 3 "needs" you listed.

But these do fit the bill for all three pretty well.

 

[MBAKER]

Re: Replacement engine weight vs. power

It woudl be hard to beat the TQ of the big block, but you could maybe look at a vortec headed 383 small block. Solid torquey little motor. But if you have everything to put a big block back in that might be the easiest route. Just get a good rebuild somewhere and go with it.

Or if I were doing it myself and wanted to spend a little more I would possibly consider a 400 small block but I would put that in an aftermarket block. If you go that far you could put more crankshaft in it, and make a 420,434, or even push it a little and make a 454 small block. The 400 or 420 combo would be a fairly easy build and make gobs of TQ similar to the big block.

The small block would also would save you about 200# weight.

 

[jklnhyde]

Re: Replacement engine weight vs. power

I'm certainly thinking small block, but that kinda' leaves me with an unusable Bravo 3 transom assembly, right? Or will they bolt up with minimal fuss?
If I could see into the future, I would feel comfortable with allocating $1500-$2000 for the repower and be happy with what I end up, or is that a bunch of wishfull thinking?
All four of my boats have been 19-21 foot cuddies with 3.0L Alphas or Cobras, so this Nova and V8 power is new territory. I like the low maintenance cost and great fuel economy my (current) 86 S-R Seville gets, but the Nova is probably a keeper and a year-long project, so I can be a bit flexible. Just need some good pointers from the Old Salts...

 

[MBAKER]

Re: Replacement engine weight vs. power

Are you missing only the engine? Or the drive too? Do you have all the bolt on pieces for the big block, manifolds, etc?

If you are missing the engine and drive I think you would have a hard time replaceing it all for 2000$ no matter what engine you went with. Kind of depends on what all you have now, and what all you have to replace. If you ahve to replace everything then the small block may be less expensive, but if you ahve most of the pieces then big block is prob the way to go. Even a good 350 should get what you want just for cruising I would think. But the 383 would get you some extra TQ for not much more if any more money.

 

[QC]

Re: Replacement engine weight vs. power

The Bravo 3 will help overcome any real power issues down low too . . . I like the 377 or 383 with the Bravo 3 plan a lot . . . Won't be real fast, probably high 40's, but it will cruise nicely and should get on plane OK. This is why you see a lot of pocket cruisers now with the 5.0 MPI 260 and the Bravo 3. I preach a lot that low end torque is not that important in most marine applications despite all of our insistence that it is, the Bravo 3 makes it even less so . . .

 

[jklnhyde]

Re: Replacement engine weight vs. power

Nothing left of the engine at all (manifolds, mounts, etc-all's gone!), and of the B3, only the entire outer portion (outdrive) is gone. The best case scenario I hear would be to find a decent B3 upper/lower and bolt it in to provide the added torque effect of 2 props. That would solve the issue of having an 'underpowered' engine powering the hull, right? That sounds logical enough, but can I bolt a small block to a B3?
What about the added complexity of having counterotating props? I guess I'll have to do some reading up on that drive system anyway!

 

[Maclin]

Re: Replacement engine weight vs. power

QC,

I have a different view on the low end torque "required" with a dual prop drive and started another thread. I would very much like to see your thoughts as well as others on the subject of torque and how dual prop drives can multiply it.


Sorry for the interruption

 

[tommays]

Re: Replacement engine weight vs. power

The BIII is made in many final drive ratios to suit the motor thats is pushing it


So if you seek out a used on you will need to find on geared for what ever motor you go with

 

[Limited-Time]

Re: Replacement engine weight vs. power

How about looking for a donor boat?? you can salvage the drive components you need and sell the rest.

 

[TilliamWe]

Re: Replacement engine weight vs. power

That sounds logical enough, but can I bolt a small block to a B3?

Yep, it's done every day. I have a 5.7 with a Bravo 3.

 

[wca_tim]

Re: Replacement engine weight vs. power

like some have mentioned, a 383 is a good choice and even a relatively mild build will net more torque and horsepower than the stock bigblock did...

 

[180shabah]

Re: Replacement engine weight vs. power

You've recieved plenty of good advice, but you need to sit yourself down and a have a heart to heart talk; set an honest budget.

A used B3 will eat the entire 2K you mentioned above. You still need an engine and all the other goodies we haven't discussed yet, distributor, fuel pump, carb, alternator, plus anything that is worn out, broken etc.

With the right combination of contacts and luck you could get it in the water for around 5K, but it could just easily cost double that.

 

[TilliamWe]

Re: Replacement engine weight vs. power

There is a long block 7.4MPI on Ebay right now that is only bid at $305.