2003+ Searay 340 Engine Options: 6.2 vs 8.1

[Sierra Azul]

Hello, I'm in the market for a 2003 or newer Searay 340 Sundancer (I'm also considering a 380, but pricing is currently out of my comfort zone). There are two gas engine options - 6.2 at 320HP and 8.1 at 370HP. Most have the 370HP engines. I would appreciate anyone's feedback on these engine options and there experience. Should I be patient and pay more for one with 370HP motors or are the 320HP motors just fine? Thanks in advance.​

 

[jason78]

This has been discussed here several times before so a search may yield more results than this thread will generate.

Having been a regular passenger and occasional operator of an 05 340DA I would recommend you hold out for the big blocks. There are a few people here with the 6.2 small blocks that seem to like them but as you have already observed, the majority seem to be the big blocks. The big blocks move the boat through the water very well.

 

[WIPlayDate]

I have the 8.1's and can only speak to them. We were out last night and cruised slowly down the river, on the way back it was getting close to dark so I opened them up. I have to say it was nice to have the extra power. When we sold our 260 and 240 and that seem to be a question most buyers asked about right away.

 

[Jimmy Buoy]

Although a difference of 50Hp doesn't sound like much (and it really isn't), the more important number is available torque between 2000 and 4000 rpm. The ability for the engines to twist those props to higher revs is what you will notice, especially with a full compliment of passengers. The 8.1 is a stroked big block (the stroke is longer than the cylinder bore) with substantial torque. The 6.2 is a bored out version of the 5.7 small block.

Not sure what the torque numbers are for either engine. Too bad Merc doesn't publish them.

This being said, some boats don't benefit much performance wise from big blocks due to the additional weight so near the stern. Actual 340 Sundancer owners would be the best source of information for you.

 

[keokie]

The 496's are rated at 500lb/ft and the 6.2's at about 400lb/ft. That's a pretty big difference. Jimmy Buoy is correct, the 496 is based on a stroked 454.

 

[Bodkin Creek George]

I would go with the 8.1's. We have them in our boat with V-Drives and they work just great. It's a great match for the weight of the 340 DA. If you go with the 380 the 8.1's will work a little harder as the weight jumps up to about 5,000lbs more. We had to put in a new lift to accommodate our 340 at a total discounted cost of $19,000 and change. Had a 380 been available at the time I would have purchased it, but then I would have needed a 25,000lb lift. We get 23-24 mph at 3250-3300rpm's. I think you will like the bigger engines.
Ours had the aluminum exhaust manifolds and ss risers which we replaced this year. Cost of the parts was 3 Grand and change.
Enjoy your boat,
George

 

[rondds]

Sierra
There has been a lot of discussion about engine choice in the previous generation 340 (2000,2001), which was essentially the same boat as the '92(?)- '99 330DA. The argument has always been that the 6.2s make for an under powered boat. In the newer 340, which is around 3' longer and 6 inches wider and about 3K lbs heavier, the argument is even more relevant. I'd stay away from this boat with 6.2s. You'll pay more now and get more at resale, and you won't be stuck with a harder to sell albatross.

Always buy the biggest boat with the best power package that you can afford!

 

[Good 2 Go]

Go with the big blocks, 8.1s are the right power for a 340 unless you are a dock sitter and don't run, then it really doesn't matter. As mentioned the torque is what makes the difference. I don't know the 6.2 fuel burn numbers but my guess is not much if at all better than with the 8.1s. My 04 340 with 8.1s 'pops' out of the hole, optimal cruise is about 28 mph getting .9 MPG and tops out at 42 MPH if you really need to get somewhere in hurry.

A big ditto,
'Always buy the biggest boat with the best power package that you can afford! '

 

[Hampton]

I would only consider the small block if the boat was I/O, and then only if kept in fresh water or on a lift. If it is an inboard boat, you must have the 8.1's.

 

[msballin]

One more vote for the big blocks. I've a 2000 340 with 7.4L Horizons which are actually rated at 380 hp as are the 8.1's. However, upon sea trialing an '01 340 w 8.1's I was amazed at the difference in torque. I'd think w the 6.2's, you'd be severely underpowered. Good luck with your new boat.

Additionally, Club Searay has been an invaluable resource for me. I'm so grateful for all of the input and assistance I've received when I've had issues, no matter what they were.

 

[Scottzzzy]

One more vote for the big blocks. I've a 2000 340 with 7.4L Horizons which are actually rated at 380 hp as are the 8.1's. However, upon sea trialing an '01 340 w 8.1's I was amazed at the difference in torque. I'd think w the 6.2's, you'd be severely underpowered. Good luck with your new boat.

Additionally, Club Searay has been an invaluable resource for me. I'm so grateful for all of the input and assistance I've received when I've had issues, no matter what they were.

I was going to mention the 7.4's as a possible middle ground. I too preferred the 8.1's to even the 7.4's just because of the torque. You load up a 340 with fuel, water, and friends and you will appreciate the extra power I think.

 

[ChrisP]

I'm preparing to buy a 2004 340 Sundancer with 8.1s. I've read on the forums about water leaking into some versions of the engines? Here's a pic of the engines from the boat I'm considering. Are these OK? Any input much appreciated!

 

[KevinC]

I'm preparing to buy a 2004 340 Sundancer with 8.1s. I've read on the forums about water leaking into some versions of the engines? Here's a pic of the engines from the boat I'm considering. Are these OK? Any input much appreciated!

@ChrisP:

Not sure what you expect us to be able to determine from these pictures and what you mean by a leaking. This is also a 9 year old thread that you are bringing back to life. I would suggest starting a new thread along with some real specific questions.

Also, to help this along, if you are referring to the manifolds leaking into the engine block then there is no way we are going to be able to determine that from a picture and I would suggest hiring a Mercruiser mechanic to do a full engine survey.

Other than that there are a lot of places these engines can leak This is not necessarily bad and keeping an eye on things is just part of standard maintenance practices. Ideally you should be looking over your engine before and after any trip for visual signs of issues.

-Kevin

 

[SeaNile]

8.1s all the way. Dare I say the 496 isn't even the perfect engine for the 2003+ 340. Its a big, heavy beamy boat that doesn't come to life till about 3500rpms on the 8.1s. This boat is screaming for diesels but it's just not happening.

 

[ChrisP]

Thanks for the replies! Are these 8.1s the "long blocks" I keep reading about.

 

[Golfman25]

I'm preparing to buy a 2004 340 Sundancer with 8.1s. I've read on the forums about water leaking into some versions of the engines? Here's a pic of the engines from the boat I'm considering. Are these OK? Any input much appreciated!

I assume you're talking about water ingestion which was an issue on 1999-2002 340s. The pics with the 8.1 and water lift mufflers have solved that problem.

 

[KevinC]

Thanks for the replies! Are these 8.1s the "long blocks" I keep reading about.

Long Block engine is a term traditionally associated with a rebuilt/remanufactured engine. It indicates the engine head was also included.

We do sometimes refer to these as big blocks to denote their size. Which is big

-Kevin

 

[ChrisP]

Thanks for the info gents!

 

[kenk340da]

My 2003 340 DA has 8.1s with BravoIII drives. I searched for a long time to find this combination to buy. I cruise at 3850 rpm which yields 32-33 mph on GPS. This boat launches hard and fast enough to pull skiers. I feel Mercruiser was a little optimistic with MPG, but I am so thrilled with the way the boat handles, the MPG doesn't factor. The economy with this combination is much better, without question, than V-Drives.

 

[Carl dalmas]

Hello, I'm in the market for a 2003 or newer Searay 340 Sundancer (I'm also considering a 380, but pricing is currently out of my comfort zone). There are two gas engine options - 6.2 at 320HP and 8.1 at 370HP. Most have the 370HP engines. I would appreciate anyone's feedback on these engine options and there experience. Should I be patient and pay more for one with 370HP motors or are the 320HP motors just fine? Thanks in advance.​