Upgrade or NOT?

[kwoolard]

Check out my previous thread for history on this boat motor problem:

Engine Noise

Can I upgrade my boat motor 350 with a 383, 360 hp without incurring too much cost? Can the Alpha handle this motor if I don't dog it out of the hole everytime?

Thanks.

EDIT BY Don S.
Old motor was a 1999 5.7L Mercrsuier with Alpha I Gen II outdrive.
Old motor is dead.

 

[Bondo]

Re: Upgrade or NOT?

Can I upgrade my boat motor 350 with a 383, 360 hp without incurring too much cost? Can the Alpha handle this motor if I don't dog it out of the hole everytime?

Ayuh,... I'd think the cost of the upgrade, vs. the cost of replacement with some upgrades, vs. just replacing with no upgrades,....
Would probably be somewhat equal steps of Upgradin'....

In your case,.. I'd think the bare Minimum I'd go with is the 350 with a 4bbl. carb,+ Vortec heads...
Add a 383 rotating assembley to that,+ you've got about as Good as it gets....

The Alphas life will be directly tied to the motions of Your righthand.....
Merc. put 330hp BBCs in front of Alphas for a couple of years,... They'll last Awhile...
And,...
With the new aftermarket drives,... Why Not,... They're at Disposable Pricing levels....

 

[Fishermark]

Re: Upgrade or NOT?

I know from the other post that Don suggested starting a new post with the new question... but to keep others from having to read the old post, it is also a good idea to tell what engine, etc you currently have.... here's what I copied and pasted from your original:
1999 5.7L Mercrsuier - Alpha Gen II

From everything I have read, you will be fine with the outdrive as long as you are gentle at the throttle - especially from a dead stop.

 

[kwoolard]

Re: Upgrade or NOT?

If I upgrade to the 383, vortec, 4 barrel will I have to change ignition systems or will the advance curve on the 5.7 Alpha be fine for this?

The other reason why I am leaning towards a 383 besides better low end torque, is because the HP curve shows that 360 crank HP is generated at 5000 rpms which it will probably never see. Crusing rpm would probably keep the HP output under 300 horsepower.

Just trying to decide what to spend $4,000 on to get the most bang for my buck without having to worry about replacing the Alpha every couple of years.

 

[Bondo]

Re: Upgrade or NOT?

Ayuh,... If you've got either of the T-Bolt igntions, it really shouldn't be an issue at all,....

I was headed in that direction, til my Bud, Bob dumped an complete Bravo drive/ transom in my lap, at a Steal kinda price...

I would've done it with the Alpha, if not for Bobby....

 

[kwoolard]

Re: Upgrade or NOT?

bondo, you have a 383 stroker?

I have found a few places online that sell them, but does anybody know of a reputable place to get the 383 marine long block?

 

[kwoolard]

Re: Upgrade or NOT?

Would this be too much for the alpha? 383 GM

Why do the different 383's have a large range of horespower? Assuming most of these motors are running 4 barrel carbs, does the intake make that much of a difference?

 

[Bondo]

Re: Upgrade or NOT?

Why do the different 383's have a large range of horespower? Assuming most of these motors are running 4 barrel carbs, does the intake make that much of a difference?

Ayuh,... I've got a 69 327 block at a machineshop that's getting built for the Atlantis project...
.030 overbore,+ the stroker crank nets 383"...

SBCs all come in a range of Horsepower, depending on the components used in the Build of the motor,...
All of the Components matter, think of it as a System, to reach the objective....

The 1 in your link looks to be a Real powerhouse,... The cam is abit steeper than I'm headed,...
It's got the Big valves in the heads too...
Under the Extra's colum, it does pretty good too,... Hi rise intake,+ rubber coated oil pan caught my eye...

It's probably alittle More motor than you need for your barge,...
That, to me is a Hot Rod boat motor...

 

["G"]

Re: Upgrade or NOT?

I'd be looking at the drive ratio issues with this. Seems if the alpha drive had a 350 attached it would hold a 383. You may have to re-prop but that ratio is where you will need to be careful.

 

[mkast]

Re: Upgrade or NOT?

I'd be looking at the drive ratio issues with this. Seems if the alpha drive had a 350 attached it would hold a 383. You may have to re-prop but that ratio is where you will need to be careful.

Alpha's are geared to a four cylinder, six or eight. What issues?

 

[wca_tim]

Re: Upgrade or NOT?

a somewhat mild 383 build (ie with 360 horsepower) should be fine and I bet you owuld be well pleased with it. I would not overprop it to keep the rpms down though - prop it to put max horsepower and wot right on top of each other.

Note that it is not the horsepower that will kill your drive, it's torque and your max torque is going to be at more like 3500 rpms, etc... you know the deal already, just don't absolutely hammer it out of the hole every time and keep fresh, high quality lube in the drive and i would bet money it'll last a long time...

just my two cents... and yes, a pretty economical upgrade with a significant increase in power.

 

[FreeBeeTony]

Re: Upgrade or NOT?

If I had to do it again (replace my engine), I would probably go with a stroker....although I would probably try and put one together myself......if I had the block available....but then again, I like to play with wrenches.

I will be looking for your performance numbers if you decide to go with the 383.

Another thought.....I'd be interested to know how Raul (@ Rapido) would be willing to help here.....not sure if he builds a 383.

Good luck!!

 

[Cptkid570]

Re: Upgrade or NOT?

I was thinking the same thing that FreeBeeTony just said --- find out how much Rapido Marine (Raul is the contact there) would charge for a 383 (if they make them).

Are you planning on doing all of the work yourself? If that's the case, you could take that $4K insurance check, buy a reman longblock from Rapido (shipped to your door), do all of the labor yourself, and make a very nice profit off of this.

 

[kwoolard]

Re: Upgrade or NOT?

I'm definitely doing all the work myself, I love to learn and tinker on this stuff, just wish the wife would understand

I've emailed Raul over the weekend so hopefully he'll get back to me soon.

Done a lot of reading on the 383's over the weekend, and some who have made the swap were not that impressed with the performance. Most stated not much noticeable gain in low end torque, rpm's didn't increase with the same prop and had about 10-15% increase in fuel consumption.

Hard to beleive it wouldn't make that much difference......hell, i'd be better of to put a Bravo on it and get the increase in torque that way. A friend of mine changed over his 350 alpha over to a 2.2 ratio bravo and said he could feel a big difference.

It's a tough decision, I may just stick with what I have but just upgrade to a 4 BBL and rebuild the old block to a 383 as money and time permit. Maybe my old 350 just wasn't performing up to par and that is where my underperformance came from....just some wishfull thinking.

 

[Cptkid570]

Re: Upgrade or NOT?

You'd probably notice a big difference switching to a 4bbl.

If I was in your shoes, I'd get a remanufactured long block from rapido, see if Raul can throw in a 4bbl intake manifold with it. I think you'd have plenty left over to buy yourself a rebuilt carb off of ebay

Then, IF you aren't happy with the performance, then you can deal with a machine shop and your 383 idea.

Others on here will reply to the power difference between a 2bbl carb and 4bbl

 

[kwoolard]

Re: Upgrade or NOT?

What will upgrading to a 4 barrel carb and intake get me on this vortec block?

Will the performance increase outway the fuel consumption increase?

I was thinking about going with this option here and adding an edeblrock 1409 carb to it. I feel more comfortable with a new engine vs. a reman and this one comes with all new tin, balancer, and water pump.

New GM Vortec 350 Long Block

I just don't want to put the money in the 4 barrel upgrade and the boat just gets thirstier and more of a dog out of the hole.

 

[FreeBeeTony]

Re: Upgrade or NOT?

If you're going to go for a Vortec long block you will need a new manifold anyway......so you might as well put on the 4bbl.......not sure if I have even seen a 2bbl Vortec intake. I wouldn't even think of putting on a 2bbl!!

As far a new vs. reman'd......I am very satisfied w/ my Vortec longblock from Rapido.

Was ~ $1K less than the eng in your link w/o the tin/balancer/water pump delivered to my house.

Note: make sure you plan for which fuel pump you will be using.....mech vs. electric

 

[kwoolard]

Re: Upgrade or NOT?

My old 1999 block was a vortec with 906 casting heads and it was a 2 bbl MerCarb. That's why i was asking if the 4bbl would be a big improvement since i already have vortec heads and intake for the 2bbl setup.

i have an electric fuel pump now, was the block a 4 or 2 bolt main, 1 or 2 piece rear main seal? Does he have blocks that don't have the mechanical fuel pump provision or will I need the block off plate?

I guess I should be asking Raul these questions.

 

[Bondo]

Re: Upgrade or NOT?

I wouldn't even think of putting on a 2bbl!!

Ayuh,... Agreed.... It's a Solid 20+hp difference...

Fuel economy is a function of Your righthand, Not the carb choosen....

 

[FreeBeeTony]

Re: Upgrade or NOT?

My old 1999 block was a vortec with 906 casting heads and it was a 2 bbl MerCarb. That's why i was asking if the 4bbl would be a big improvement since i already have vortec heads and intake for the 2bbl setup.

OH......I would still go with the 4BBL...

i have an electric fuel pump now, was the block a 4 or 2 bolt main, 1 or 2 piece rear main seal? Does he have blocks that don't have the mechanical fuel pump provision or will I need the block off plate?

My block was a 1pc rear main seal, roller cam, 2 bolt main w/ a mech fuel pump.....

Give Raul a call.......what did he say about the 383???