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Looking to repower with a 496 Mag HO

P

Plaineman

New member
Hello all...

I have a 2000 259 Convincer that originally came with a Merc 7.4 MPI (Gen VI) and it has seen its last run. I am looking at a 2005 496 Mag HO and was wondering if anyone knows how much modification I may have to do to fit this motor in. It looks like all the mounting will be an even swap but there are a couple of things that concern me. One is the fact that the boat that the new engine is coming from has a full hydraulic steering set up where mine is cable. I noticed that the pump on the new motor is completely different. Am I going to have an issue with this... also, will the electrical plug be a good fit. From what I understand some are 10 pin and some are 14 pin. The owner of the new motor also says he will include the smart craft gauge that can be installed in the dash where the tach is. How much trouble am I in for with this swap.

Any insight greatly appreciated.

Thank you,

Brian
 
I don't think it will be that bad of a swap at all. With the power steering, I would think the fitting would be the same going into the pump as what you have, you just might have to replace some hoses to make up for different lengths. As far as the plugs go, I'm not sure. I'm not sure where you are located, but Jason at Kunkel's Marine in Ontario, Ohio is very knowledgable about this sort of thing. You could probably call the Checkmate factory as well, I'm sure somebody there could help ya out.

One thing to do if you are going to run the stock 496 exhaust is remove the turbulators. A good friend of mine and mamner on here (lcboater) removed his on his 300 Convincor last year and the sound improvement of the exhaust was awesome!!! I think he might have even gained a mph or so too. Maybe send him a PM on here, his name is Barry and he's a really nice guy and knows a lot about those motors as well. He might be able to give ya some advice.
 
I would not mess with any 496, runs great for a while...they did not keep that engine all that long for a reason...back to 502 now
 
Everybody I know that has one is very happy with it. Barry (lcboater) has 400-500 hours on his, running a procharger, with no issues at all.
 
I too know a number of people with 496 Mag HO's installed... I have a buddy that bought a brand new 30' Baja with twin HO's and since it is his first boat he often has me captain it and I have to say they run like a charm. I have heard that if you add only a pro charger and do nothing else to it that you have to baby it to have it last... otherwise the bottom end will give out. But for now if I can get my Convincer up close to 70mph with a 40 or 50mph cruise I will be a very happy guy. We will see what happens in the spring when I install but for now the price is right and the seller lives close by so it looks like I am going to move forward.

Thanks guys!
 
Won't be bad long as up got it complete from front to back top to bottom. There are 2 different main harness config. May have to. Change harness depending on what you use the pins are numbered and a merc manual will tell you what they go to. Hopefully you got flywheel coupler etc. Those bolt patterns have changed throughout the years
 
Jason y said:
Won't be bad long as up got it complete from front to back top to bottom. There are 2 different main harness config. May have to. Change harness depending on what you use the pins are numbered and a merc manual will tell you what they go to. Hopefully you got flywheel coupler etc. Those bolt patterns have changed throughout the years
Click to expand...

Yep... got the whole deal.... with coupler and all. I am thinking this should all go in pretty well. My convincer is a 2000 model year and the motor is an 05. I do understand a lot can happen in 5 years but the basics are all the same. I also understand I should be prepared for some snags along the way but this summer she will RUN!!!!!

Thank you

Brian
 
Jason y said:
Pretty sure 496 manifolds have bigger flange bolts than 502 454.
hopefully you get them.
Click to expand...

I can't speak for the bolt size, but I know the 496 manifolds are a direct bolt on to a 454/502. They are actually great flowing manifolds. My dad has them on his 454 that makes 625+hp. They work and sound great
 
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