The real differences between 496Mag & HO
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The real differences between 496Mag & HO
Being new to the boating world I found the most difficult decision after settling on a brand and model was what type of engine to get. With all the different engine options it'll make you Finally I decided on a Big Block, but which one? The MAG or HO? My Baja dealer wanted $7,500 for the HO upgrade. I found this to be outrageous. Having done some work on GM cars previoulsy I opted for the regular Mag496 375hp version instead, thinking that it would be cheaper to upgrade it in the long run.
So after my purchase I bought all the manuals from Mercruiser, including the Parts Manual. I took a highliter and went through every page hilighting only when there were different part numbers for the same part. Here is what I found.
Decal HO pn#37-863307 vs. Decal Base pn#37-863306
PCM HO (Mechanical Throttle & Shift) pn#866091T01 vs. PCM Base pn#866090T01
Throttle Body Assemble HO pn#863379A06 vs. Base pn#863078A06
Camshaft HO pn#431-881628 vs. Base pn#431-881627
That's it boys & girls! A whopping 4 different pn#'s for and entire engine assembly and one of them's a sticker!
Some notes of interest. Same pn#s for ; fuel injectors, crank ( I was afraid that one might be forged while the other not), fuel rail and fuel pressure regulator kit. Different pn# for the throttle bodies but same hardware. (Source: Ray from Raylar)
So now all I need is a solid contact for Mercuriser Parts to start arriving at my doorstep. Can anybody recommend somebody who sells parts cheap, like 10% over cost.
Sebastien
So after my purchase I bought all the manuals from Mercruiser, including the Parts Manual. I took a highliter and went through every page hilighting only when there were different part numbers for the same part. Here is what I found.
Decal HO pn#37-863307 vs. Decal Base pn#37-863306
PCM HO (Mechanical Throttle & Shift) pn#866091T01 vs. PCM Base pn#866090T01
Throttle Body Assemble HO pn#863379A06 vs. Base pn#863078A06
Camshaft HO pn#431-881628 vs. Base pn#431-881627
That's it boys & girls! A whopping 4 different pn#'s for and entire engine assembly and one of them's a sticker!
Some notes of interest. Same pn#s for ; fuel injectors, crank ( I was afraid that one might be forged while the other not), fuel rail and fuel pressure regulator kit. Different pn# for the throttle bodies but same hardware. (Source: Ray from Raylar)
So now all I need is a solid contact for Mercuriser Parts to start arriving at my doorstep. Can anybody recommend somebody who sells parts cheap, like 10% over cost.
Sebastien
Last edited by saubouin; 01-14-2005 at 08:22 AM.
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Re: The real differences between 496Mag & HO
Before you go wasting a lot of money upgrading your 375 mag to a 425HO, check out our website at www.raylarengine.com for some decently priced upgrades that will give you 525HP.
Ray @ Raylar
Ray @ Raylar
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Re: The real differences between 496Mag & HO
Looks like the php/mysql dbase on the forum went down today. I'm going to repost some of the answers to questions which were posted on this thread earlier.
The PCM is a different pn# hence different programming. I recall reading from other members that the HO redline was 5,4xx rpm vs. the 5,000 rpm redline on my regular 496 MAG.
Raylar,
I have already bookmarked your web page. Congrats on a great product!
However, I have to disagree with your original post as it being a waste of money to upgrade my 375hp to 425hp. If by replacing 3 factory parts I can gain 50 hp including a properly tuned factory PCM to match the cam and power output for the upgrades, then how am I wasting money? Your $5,800 package, a good tune, add $799 and now your at $6,500, or $65 per horsepower.
So far I have acquired 2 of the 3 pieces (cam and new throttle body) I need for the puzzle and have only spent $250. Let's say worse case scenario the 3rd piece costs me full retail ($1,200) So thats $1,200 plus $250 equals $1,450 or $29 per horsepower. So how am I wasting money now? Also my 50 hp package has been tested on thousands of boats so it is safe to say it is a very proven upgrade. With all the 496 MAG owners doing supercharger upgrades, engine builds etc there will be a lot of manifolds, heads, camshafts, etc.. on EBAY or in various other classfieds that can be picked up at a very substantial discount over purchasing them from Mercruiser. In my case I have a forum member who is shipping me the entire intake manifold, pcm harness, throttle body, injectors, camshaft, 496MAG HO engine cover for $250 !!! This is why I love the internet baby!
Happy Boating!
Sebastien
Sebastien
The PCM is a different pn# hence different programming. I recall reading from other members that the HO redline was 5,4xx rpm vs. the 5,000 rpm redline on my regular 496 MAG.
Raylar,
I have already bookmarked your web page. Congrats on a great product!
However, I have to disagree with your original post as it being a waste of money to upgrade my 375hp to 425hp. If by replacing 3 factory parts I can gain 50 hp including a properly tuned factory PCM to match the cam and power output for the upgrades, then how am I wasting money? Your $5,800 package, a good tune, add $799 and now your at $6,500, or $65 per horsepower.
So far I have acquired 2 of the 3 pieces (cam and new throttle body) I need for the puzzle and have only spent $250. Let's say worse case scenario the 3rd piece costs me full retail ($1,200) So thats $1,200 plus $250 equals $1,450 or $29 per horsepower. So how am I wasting money now? Also my 50 hp package has been tested on thousands of boats so it is safe to say it is a very proven upgrade. With all the 496 MAG owners doing supercharger upgrades, engine builds etc there will be a lot of manifolds, heads, camshafts, etc.. on EBAY or in various other classfieds that can be picked up at a very substantial discount over purchasing them from Mercruiser. In my case I have a forum member who is shipping me the entire intake manifold, pcm harness, throttle body, injectors, camshaft, 496MAG HO engine cover for $250 !!! This is why I love the internet baby!
Happy Boating!
Sebastien
Sebastien
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Re: The real differences between 496Mag & HO
Originally Posted by Payton
The big difference is 50hp will net you about 1 mph.
Shirley you can't be serious?
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Re: The real differences between 496Mag & HO
Originally Posted by saubouin
So on my 24 foot Baja that weights 4,400lbs I'm only going to see 1mph on the top end?
Shirley you can't be serious?
Shirley you can't be serious?
I dont know about you but 145hp made a huge difference to my boat at 4500lbs
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Re: The real differences between 496Mag & HO
Originally Posted by saubouin
So on my 24 foot Baja that weights 4,400lbs I'm only going to see 1mph on the top end?
Shirley you can't be serious?
Shirley you can't be serious?
Actually, you'll probably 2-4mph on the top end with 50hp. Been there, done that on a 24 Outlaw. Bumped a tired 365hp up to about 420hp and saw a 4mph gain.
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Re: The real differences between 496Mag & HO
Originally Posted by Griff
Actually, you'll probably 2-4mph on the top end with 50hp. Been there, done that on a 24 Outlaw. Bumped a tired 365hp up to about 420hp and saw a 4mph gain.
2-5 is more inline with what I'm expeting. If at the end of the day I only get 1mph I'll be a little bummed but will post my results nonetheless.