What engine?

CAGE RATTLER

CAGE RATTLER

New Member
Apr 10, 2009
400
Essex, MD
Boat Info
85 Amberjack 255
Engines
2010 496 MAG MPI
I think im going to repower my 85 Amberjack 255. I have a 2003 350 Mag MPI in it now and am thinking of going to a big block.

Does anyone know if these boats came stock with a big block??

Just wondering if i'll need to re-do my stringers for the larger motor.

Thanks
 
Don't know about big blocks, but the AJ did come with twin small blocks. I think a big block would be ok, but others will chime in who are more familair with your boat. Try the Sea Ray archives to see if they list power options.
 
I have considered this also. I was told by several mechanics that its not going to give me the desired outcome. They made a lot of these boats with twins because it is heavy boat with a large beam. I feel your pain, but increasing your engine size may give you only a marginal improvement in performance. Sorry to be the bearer of bad news.
 
Big Island Lifer said:
I have considered this also. I was told by several mechanics that its not going to give me the desired outcome. They made a lot of these boats with twins because it is heavy boat with a large beam. I feel your pain, but increasing your engine size may give you only a marginal improvement in performance. Sorry to be the bearer of bad news.
Click to expand...

Might want to have your mechanics read this article from boating world. the days of the big block 7.4 with only 330 HP are long gone.

http://www.boatingworld.com/engine/pages/KingoftheHilla5dedd3b.aspx

My 350 MAG MPI will top out around 33 MPH but that new 8.2 big block should get me near 50+ mph.
That doesnt sound like marginal improvement to me :grin:

But OUCH ......... Im sure the price tag will hurt a bit.
I've already got more money in my boat than she's worth...lol.
 
The financial return is what I am more interested in. You can always go bigger but when does it stop making sense financially. That number is different for every boater. Like you I have put more money into my boat than it is worth to someone else. If your hull is in good shape and you plan on keeping the boat then go for it! I would love to hear about your results- who knows maybe I'll have to recalculate my own protocol. :grin:

With regards to the 8.2 MAG H.O- What does it cost to replace the Catalytic converters? What is their life expectancy?

On another note- How many more 255/ 270 amberjack owners are on here? Have there been many posts on our boats?
 
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Motor mounts are at the same location BB vs SB.
I just read this morning the 2010 Merc 8.1 Mag does not require the cats on the 2010 engine.
 
I have considered the 350 HP 383 Stroker but not the 400 HP scorpion stroker. That takes 91 octane to run and not sure i'd feel comfortable running at 6000 RPM's .... lol.

Only thing that worries me about those engines is their already punched out and running on edge if you know what i mean. life expectancy on those cant be as good as running a stocker.
 
Tail Chaser 661 said:
Motor mounts are at the same location BB vs SB.
I just read this morning the 2010 Merc 8.1 Mag does not require the cats on the 2010 engine.
Click to expand...

Thats good to know.

What kind of performance are you getting out of that 496 in your DA? Did you move up from a SB?
 
CAGE RATTLER said:
Thats good to know.

What kind of performance are you getting out of that 496 in your DA? Did you move up from a SB?
Click to expand...

YEP!
I had the 260 hp 5.7 with the Alpha 1 drive.
I had so many delays with parts, fuel tanks etc last year that I had to walk away from it.

Keokies identical boat with the 502ci. (Same TQ as the 496ci) 53mph WOT. 2.0/2.3 mpg at 3000rpm doing 30 mph.
Redline on the 496ci is 4700rpm. The 502ci is 5000 rpm.
Keokie mentioned the 496ci has more mid range grunt. Maybe better cruise numbers with the 496ci:huh:
 
I still havent pulled the trigger yet on the new engine and was hoping someone here could help me make my mind up for me.

I was about ready to take the plunge on the 383 bravo stroker reman till i found out i cant get it with full fresh water cooling. just the half kit.

Im still debating on the 383 but just not quite sure the added 25 HP will be what im looking for especially with a price tag of around $9000. I can get a long block for my water injested 350 Mag MPI for around $2500 but then will still need new manifolds, risers and I may need a new flywheel as well (thats another story). Is the swap of the long block very difficult? Im a pretty decent backyard mechanic but working on marine engines makes me a bit nervous.

Im also considering a BB 496 or 496 HO which will run me about $12000 - $14000 I believe but comes will full FWC standard. Im just not sure if i'd have to do any other modifications to add the BB. Anyone know what, if anything, will need to be changed to add the BB?? (Throttle or shifter cables or whatever?)

Anyone know of any good deals on any of these motors or maybe a lightly used one for sale??

Ive been looking at the Michiganmotorz.com website.
http://www.michiganmotorz.com/complete-turnkey-engines-turnkey-engines-c-31_49_79.html

Please offer up some advice .............. summer is here and ive been researching and researching for about a month, the best way i know how and i need to make a decision and take the plunge and get the ball rolling. Im at least hoping to get splashed before the 4th of July weekend and I still have alot of other things i wanted to work on before splashing.

Thanks
 
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The one thing you need to take into concideration with the stroker is not the HP but the torque band. Strokers make great low end torque this will get you up on plain faster. Auto racers like the 383 because it gets the car back up to spedd out of the turns faster. If you want speed I would recommend a big block that makes more HP at lower RPMs and doesn't run on the "raged edge" of reliablity. Just my opinion. I'm going to up grade my little 5.0 this winter with better fueling and exhaust. I'll leave the lower end pretty much stock to make for a trouble free engine. Check to make sure your drive can take the added torque of the 383. You may end up destroying it as it will be hte next weakest link in the chain.
 
CAGE RATTLER said:
I still havent pulled the trigger yet on the new engine and was hoping someone here could help me make my mind up for me.

I was about ready to take the plunge on the 383 bravo stroker reman till i found out i cant get it with full fresh water cooling. just the half kit.

Im still debating on the 383 but just not quite sure the added 25 HP will be what im looking for especially with a price tag of around $9000. I can get a long block for my water injested 350 Mag MPI for around $2500 but then will still need new manifolds, risers and I may need a new flywheel as well (thats another story). Is the swap of the long block very difficult? Im a pretty decent backyard mechanic but working on marine engines makes me a bit nervous.

Im also considering a BB 496 or 496 HO which will run me about $12000 - $14000 I believe but comes will full FWC standard. Im just not sure if i'd have to do any other modifications to add the BB. Anyone know what, if anything, will need to be changed to add the BB?? (Throttle or shifter cables or whatever?)

Anyone know of any good deals on any of these motors or maybe a lightly used one for sale??

Ive been looking at the Michiganmotorz.com website.
http://www.michiganmotorz.com/complete-turnkey-engines-turnkey-engines-c-31_49_79.html

Please offer up some advice .............. summer is here and ive been researching and researching for about a month, the best way i know how and i need to make a decision and take the plunge and get the ball rolling. Im at least hoping to get splashed before the 4th of July weekend and I still have alot of other things i wanted to work on before splashing.

Thanks
Click to expand...

I picked up my new 2006 8.1 Mag for 10K last year.
 
Build it yourself we just built a fully forged 496 with alum. Heads 4 bolt main got it dynoed at 530hp and 600lb torque cost us 5100 to build.
 
If it was up to me I would stick th the small block easier and cheaper to fix its lighter and you can still get 500hp out of it for 4000
 
OldSkool said:
The one thing you need to take into concideration with the stroker is not the HP but the torque band. Strokers make great low end torque this will get you up on plain faster. Auto racers like the 383 because it gets the car back up to spedd out of the turns faster. If you want speed I would recommend a big block that makes more HP at lower RPMs and doesn't run on the "raged edge" of reliablity. Just my opinion. I'm going to up grade my little 5.0 this winter with better fueling and exhaust. I'll leave the lower end pretty much stock to make for a trouble free engine. Check to make sure your drive can take the added torque of the 383. You may end up destroying it as it will be hte next weakest link in the chain.
Click to expand...

I understand about the torque diference but the BB has even more torque. anyone know what the torque specs are on the 350 MAG MPI? Havent been able to find that info.

I have a bravo 1 OD so no probs moving up to a BB there.
 
I posted the tq numbers of the 5.7 through 502ci in the past. I found that lack of appreciation giving out much researched info online was a waste of my time.
 
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Actually I do remember seeing the specs you posted but i have a horrible memory and should have written them down. When i do a google search, Ive had a hard time finding the torque specs for the 350 MAG.

I appreciated all the specs you gave in your repower thread. they've helped me quite a bit in making a decision. Ive probably read that entire thread 3 or 4 times.

I'm leaning heavily towards a 496 MAG MPI or the HO version. Just trying to find the best price I can right now and trying to find out what, if anything, I will need to change over for the BB install.
I'm waiting to hear from Riverside Marine right now. They are turning one of their locations into a repower center but I wasnt real happy with the salesman I talked to today. He doesnt seem to know much at all about the Mercruiser engines. But if they can get me a good price, I would rather deal with someone local instead of an internet company.

Quick question ...... Will the bravo coupler & Y pipe off my 350 mag also work with the BB?
 
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