The Boating Forum - Verado 350 Sci vs Optimax 300XS

THE HULL TRUTH is the world's largest FREE network for the discussion of Boating & Fishing. Whether you're researching a new boat, or are a seasoned Captain, you'll find The Hull Truth Boating & Fishing Message Forum contains a wealth of information from Boaters and Sportfishermen around the world.

View Full Version : Verado 350 Sci vs Optimax 300XS

08-15-2010, 05:16 PM

I hope you are well :)

I have a Phantom 25 offshore hull (race hull mid 1980-ties Great Britain Endurance race) with twin Merc 2,5 EFI SS engines (280 hp each). The services and fuel costs are too much to handle unfortunately, so I am to sell the engines this winter. Top speed is 87-88 mph. The weight of the boat is approx. 3,000 lbs wth the driver.

Before I mounted the twin engines, I had a Promax 300. Not the x version. The boat ran 76-77 mph spinning a Tempest 25 at 6150 rpms.

I am considering buying a Verado 350 Sci, alternatively a Optimax 300XS. I have been reading about the Verado performance. Have anyone of you compared the 350 vs 300XS?

I have read about the upgraded lower unit. Does it have waterintake in front of the bullet, or only on the sides? I used a Torque master lower unit on my PM 300. Since the speed is lower than 85 mph, there will be no need of a nose cone version. However, I am curios about this new lower unit. How high can it be jacked compared to a Torque Master? Approx the same? Is the new version thicker than the first version, or just longer (looks longer on pictures)

Would it be possible to mount a Torquemaster lower unit on the mid section instead of the stock lower unit?

Thanks for your help!

Cheeers Toffen

08-15-2010, 06:30 PM
my 250xs' have fleetmasters w/ low water pickups (that's what they call the ones with holes in the front of the bullet). Pretty sure the 300XS has the LWP's too. Not sure about the sci but you should be able to find out on the Mecr racing website.

08-15-2010, 08:22 PM
The services and fuel costs are too much to handle on your 2.5's so you are going to drop 30 grand on new engines?

08-15-2010, 10:31 PM
ive had a 300xs and 350sci on the same hull, single engine application. top end performance is within 1mph, however the sci is burning 34gal and hour whereas the opti is burning 24gal an hour. for what its worth, a 300 verado gear case on the sci is worth 3mph on a 24 yellowfin.

08-16-2010, 03:27 AM

Thanks :)

The service costs for using my 2.5 EFI's are approx. USD 8,500 (Norway is not a low cost country) plus fuel and oil costs. In all approx USD 18,000 for 40 hrs use...

The service costs, fuel and oil for one 300XS / 350 Sci running in average 4,000 rpms 40 hrs are approx. USD 9,500.

I can sell the two engines for approx. USD 25,000. A new engine cost if bought in US and plus local taxes; Optimax 300XS USD 16,000 plus local taxes = 28,750 and a Verado 350Sci USD 23,500 plus local taxes = USD 40,000. If bought in Norway, add 40%...

The difference between a new 300XS and selling the two engines are not much. Buying a 350 Sci is more ofcourse. If it only add 1 mph with the new lowr unit, it is not worth it. However, if it is possible to use a Torquemaster lower unit on it - the 3 extra mph will be.

So the question is if its possible to add a Torquemaster lower unit used on a 300XS / Promax 300 to the 350 Sci. I have one spare.

How does the 300 Verado lower unit work on the 350 Sci? Does it hold up at all?

Speak soon and thanks for your help.

Cheeers, ToffenG

08-16-2010, 04:19 AM

I just spoken to a local dealer and he told me that 350 Sci now comes with a 3rd edition lower unit. It looks much like a NTX drive. I did see a new 350 Sci mounted on a Cougar Rib the another day, and this engine did have a lower unit not with a regular torpedo shape. Do you know anything about this?

Cheeers, ToffenG

08-16-2010, 09:59 AM
Homesite would love to find out about these new lowers I'll bet.:Q

08-16-2010, 10:19 AM
Yeah where is Homesite ;?

08-16-2010, 10:25 AM

I am not sure if its true if a new version is out there, but the new 350 Sci I see in the harbour did have a lower unit with a shape like the NTX drive. Not that typical torpedo shape. Smaller in front than back, and a little square like.

Is it possible to mount a Torquemaster lower unit to a 350 Sci. Or is a regular 300 lower unit just as strong. I ran a upgraded Promax 300 (SVS etc) with a Torquemaster for many years with good results. And the lowr unit is fast.

Cheeers, ToffenG

08-16-2010, 10:49 AM
Contact Joey at He should be able to answer your questions

08-16-2010, 03:06 PM

I have investigated a little. You can put your 300 Verado gear parts inside a Sportmaster and Torquemaster housing. However, you can not use a complete Sportmaster and Torquemaster lower unit on 350 Sci. The driveshafts do not fit. I got this info from who is familiar with both 300XS and 350 Sci. If there are no new 3rd edition lower unit for 350 sci, the easiest will be to buy a 300 Verado lowr unit complete, and use the 350 sci verson as spare. Its another USD 4,000 though. Lets hope a 3rd edition lower unit exists :)

Cheeers and thanks, Toffen

08-16-2010, 04:26 PM
You can use the Sportmaster/Torquemaster you just have to have the drive shaft resplined or swapped out to the four stroke one vs the optimax one. The splines that go into the powerhead are different, thats it.

08-16-2010, 09:54 PM
Sounds like the easiest and cheapest way is to get the 300XS, just as fast with less fuel!!

08-17-2010, 02:06 AM

Thankts Captone :) The Verado 350 sci consumes approx. 40 litre at 4,000 rpms. The Optimax 300XS consumers approx. 42-45 litre at the same rpm. Since the 350 Sci will propped with a smaller prop due to higher wot rpm, the figures will be the same per distance. 4,000 rpms is my normal cruise speed.

Cheeers, Toffen

08-17-2010, 08:18 AM
dont know where youre fuel burn numbers are coming from, but i assure you the 300xs is more efficient, across the board. these are numbers taken from the same hull

when propped for 6400rpm, burns 8.5gph at 4000rpm, 23.5-24gph at wot.
when propped for 6100rpm, burns 10gph at 4000rpm, 23.5-24gph wot.

when propped for 6800rpm, burns 10gph at 4000rpm, 34gph at wot.
when propped for 6500rpm, burns 11.5gph at 4000rpm, 34gph at wot

my boat ran 69 with the 300xs, and runs 70 with the 350sci. because its short on revs, the 300xs spins a bigger wheel to run the same speed. as a result, it not only burns less fuel at cruise, its running faster as well. at 4000rpm, i was able to cruise at 4.5mpg with the 300xs whereas the 350sci is 4mpg. both engines are even more efficient at 3500rpm. the 350sci really drinks fuel over 4000rpm whereas the fuel flow is more linear on the 300xs.

08-17-2010, 09:18 AM

Thanks for this :)

Good to know. I got the 300xs figures from a friend plus the magazine bass & walley boat magazine. The Verado figures I got from actionrib company in Denmark. They use 350 sci on their 8,5 meters ribs.

Here are some figures:

8,5 meters rib:

2000 RPM: 15,2 L/H
2500 RPM: 18,6 L/H
3000 RPM: 24,7 L/H
3500 RPM: 32,4 L/H
4000 RPM: 40,5 L/H / 10,65 GPH
4500 RPM: 51,6 L/H
5000 RPM: 65,1 L/H
5500 RPM: 85,0 L/H
6000 RPM: 110 L/H
6500 RPM: 119,8 L/H

Bass And Walley Boats test of a Bullett 21XRD

At a barely turning 2500 rpm and 29.7 mph, we recorded a stingy 4.4 gph—which computes to 6.7 mpg. When we dropped the hammer a little and brought the engine to 4000 rpm (almost 60 mph), we still only burned 12 gph, which is 5 mpg.

Engine Speed Fuel Economy Sound
(RPM) (MPH) (GPH) (MPG) Range (mi.) dB-A
1000 5.2 1.7 3.1 99 -
1500 6.4 2.9 2.2 72 -
2000 9.9 4.1 2.4 78 -
2500 29.7 4.4 6.8 220 -
3000 40.1 6.9 5.8 188 -
3500 49.4 9.7 5.1 165 - / 36,9
4000 59.7 11.9 5.0 162 - / 45,22
4500 67.8 14.9 4.6 149 - / 56,62
5000 78.5 16.4 4.8 156 -
5500 87.6 20.2 4.3 139 -
6000 96.5 24.5 3.9 126 -
6250 (WOT) 101.4 26.1 3.9 126 -

I have read a few posts now about 300xs vs 350 sci, and for some people the 300xs is almost as fast, for others the 350 sci is 3-4 mph faster. So it will depend on the set up in the end. The question is ofcourse if its worth the extra money :)

I have a torque master lower unit from my PM 300, so I can use that and pick up speed. And of a new type lower unit is on its way, it will also add to the decicion making process.

Cheeers, ToffenG

09-13-2010, 03:09 AM

Got this email today:


I have heard that there are some questions coming in looking for Verado
models with the new Poseidon gearcase. I just wanted to reiterate that the
start of production for the Poseidon-equipped Verado models is as follows:

Standard Poseidon (black finish, 1.85:1 ratio, 1" propshaft): September
26, 2010
Heavy Duty Poseidon (silver finish, 1.75:1 ratio, 1.25" propshaft):
November 26, 2010

The sales forecast that you will submit with the next submission should
reflect the new model codes in the file here-below with starting sales
forecast month as follows:

Verado 225 -300 HP: October 2010
Verado 350: December 2010

Your sales forecast for the months prior to the months here-above still
needs to show the current model codes.

The dealer network will be informed of the new gearcase via a service

Please also bear in mind that a multi-engine boat must run either all
Verado (current) gearcases or all Poseidon gearcases, but not a combination

I am not sure how the new Poseidon gearcase will look. And if its faster. Time will show.

Cheeers, ToffenG

09-13-2010, 06:14 AM
I have some extensive experience with both of these engines..
In your application I would stick with the 300XS.
Snappier throttle response..
Not to corect anyone here... But..
The 300XS when properly propped and on stock mapping burns 28.75 GPH at WOT.
The 350 SCI burns the number that was stated..

IN our testing.. The 300XS and 350 SCi were about close with the 300XS being a little more efficient considering oil burn in one engine versus oil changes costs in the other.

The gear boxes are a big difference..
The 350 SCI box is a little slower.. With the 300 Verado case on the 350 SCI makes this motor VERY fast but,,, there is a possible failure downside.

The 350 box does not like to be lifted to much where the 300 Verado box is ok with it..
The 300XS has many options in Cases, sounds like the torque master would be your best bet.. Yes it has holes in the front of the cone..

We found with the 350SCI vs 300XS there was a 4-5 mph difference in speeds with SCI being the fastest.. BUT we were not using the new style SCI case. And our 300XS had torque master. We did not run the new case to adjust production testing..

09-13-2010, 09:25 AM


Have you ever compared how high you could run the torquemaster vs old style verado lower unit vs the 2nd gen lower unit. I have been reccommended to block the three upper waterholes to get the lower unit higher. I did the same with my torquemaster lower unit back in time. My torquemaster did not have holes in front. Just on the sides. The trick is to get the lower unit out of the water without loosing psi and bowlift. I am curious how the poseidon lower unit will be in that department ...

Cheeers, Toffen

09-13-2010, 09:36 AM
Toffen I would think that the poseidon lu would address those issues and perform better for the 350 SCI. Will be interesting to see the numbers.

09-14-2010, 05:17 PM

Also learned today that 300xs need 96RON which most marinas do not offer. So I have to carry 20 litre jerrycans as with the 2,5 EFI's... The 350 sci runs on regular fuel 95RON in Norway, and I can use the marinas. 300xs warranty period is also scaled down in Norway to one year. The normal is at least 2 years. 350 sci will have 3 years warranty. So I smell 350 sci :)

Cheeers, Toffen

09-14-2010, 07:41 PM
where is this info coming from? the fuel and warranty are the same with the 300xs and 350sci...

steve... im curious about the 28gph from the 300xs. the two 300xs motors ive run with 20" ecu's have never burnt even 25gph?

09-14-2010, 08:15 PM
I have owned 14 300 xs's and they all burnt 24-25 gph at WOT, when it is very cold out they will burn up too 26 gph.

09-14-2010, 08:15 PM
I have had one Pre production motor and production.. both burned in the high 28's I will check again this week to update that.. I have one on a LAB that I can put in the corner at 6350.

09-24-2010, 07:58 AM

Sorry for the delay here.

This is the info I have from dealer in Norway. 1 years warranty for 300xs and 3 years for 350 sci. It used to be 2 years, which is common in Norway, for the 300xs. But its likely to be reduced for 2011 season.

300xs runs on 96RON in Norway. If you are to use such octane, the nearest is 98RON. 95RON is too low. 350 sci runs on 95RON in Europe.

Cheeers, Toffen

where is this info coming from? the fuel and warranty are the same with the 300xs and 350sci...

steve... im curious about the 28gph from the 300xs. the two 300xs motors ive run with 20" ecu's have never burnt even 25gph?

09-24-2010, 08:29 AM
i didnt know the 300xs needed HIGHER octane than the 350sci which needs premium. Also, toffen, where are u getting your info from? You dont post who the sender of that info is?

09-24-2010, 10:37 AM

A couple of dealers in Norway have mentioned this to me. And in the specs at Mercury Racing, it states that 300xs need 96RON. Which we do not have in Norway. We have 95RON and 98RON. The 350 sci runs 95RON in Europe according to a newsletter from MercuryRacing. In US both 300xs and 350 sci runs 91 PON.

If I am to import a 350 sci from US the engine will not be CE approved, just because of the difference in fuel requirements.

I will ofcourse double check with Brunswick in Norway to be absolute sure :) Sorry for the confusion.

Cheeers, Toffen

i didnt know the 300xs needed HIGHER octane than the 350sci which needs premium. Also, toffen, where are u getting your info from? You dont post who the sender of that info is?

09-26-2010, 10:45 AM
Verado 350 SCi (U.S. version vs. EU version)
The recent release of the long-awaited Verado 350 SCi has generated a lot of excitement, and along with that some great questions and discussion topics. Perhaps one of the most misunderstood subjects is the Verado 350 SCi’s fuel grade requirement, and why it differs between models sold in the US vs. EU (European Union) countries.

The EPA (US) version of the Verado 350 SCi requires 91 octane (R+M)/2, or premium fuel, which is a critical factor in ensuring the absolute highest combination of performance and fuel efficiency available while meeting EPA emissions requirements. The version sold in European Union countries requires 95 RON (89 octane (R+M)/2 equivalent) and meets the EU Recreational Craft Directive (RCD) requirements, but has different performance and fuel efficiency characteristics.

It’s important to note that emission regulations differ significantly between the EPA-regulated United States and the European Union countries, which are governed by the RCD. In addition, it is Mercury Marine’s goal to offer only the best products for our customers independent of where they operate their boats. To accomplish this, it is sometimes necessary to offer separate models with calibrations designed for specific markets. This is the case with the Verado 350 SCi, which is available in two configurations: an EPA calibration for the United States (and non-EU countries) and an EU calibration for countries belonging to the European Union.

Regardless of version, all Verado 350 SCi engines MUST run the specified fuel grade (91 octane (R+M)/2 on US versions and 95 RON on EU versions). Because the Verado 350 SCi does not include a knock protection system, running these engines on fuel grades that differ from what is specified above could result in significant engine issues. In addition, product issues that result from running non-specified fuel grades are not covered by the Verado 350 SCi’s limited warranty.

To learn more about this exciting new offering from Mercury Racing, please visit

09-26-2010, 10:49 AM
Rod fuel in Europe is not the same as here in the US. Also they figure the Octane rating differently than we do. I think that is the difference. Notice how Toffen says RON in Europe as to PON in the US. I think he made a typo on that. I also think the energy content of the European fuel is lower than the US fuel.

No typo. He got PON as another name for AKI rating. Here is from the link.

Anti-Knock Index (AKI)
In most countries, including all of those of Australia ( and Europe ( the "headline" octane rating shown on the pump is the RON, but in Canada (, the United States ( and some other countries, like Brazil[4] (, the headline number is the average of the RON and the MON, called the Anti-Knock Index (AKI, and often written on pumps as (R+M)/2). It may also sometimes be called the Road Octane Number (RdON), Pump Octane Number (PON), or (R+M)/2.
[edit (] Difference between RON and AKI

Because of the 8 to 10 point difference noted above, the octane rating shown in the United States is 4 to 5 points lower than the rating shown elsewhere in the world for the same fuel. See the table in the following section for a comparison.

09-26-2010, 01:11 PM
Does anyone have any pics or new info of the new 350v gearcase. When is it going to be released and what kind of performance improvents should we expect?

09-26-2010, 02:27 PM

The above is correct. In US both 300xs and 350 sci runs on 91 Pump Octane Number (PON). But in Europe the 300xs need 96 RON and 350 sci 95 RON. Since 300xs need 96 RON, we need to use the 98RON. Although I know some that use 95RON. But it will be on the edge.

Check out:

The new lower unit is to be released in November for 350 sci. It looks similar to the NTX drive some say.

Cheeers, Toffen

11-13-2010, 02:49 PM

Have anyone of you received any info about the new Poseidon gearcase yet?

Cheeers and thanks! Toffen

Search Engine Friendly URLs by vBSEO 3.2.0