496 mag VS. H.O.
 

Were possibly ordering a new boat, and the upgrade from the 496 mag to the H.O. is 5 grand,, wondering if the regular mag has all the same GOOD parts as the H.O. like crank, valve train, pistons, rods..

Thinking of taking the 5 grand and having AZ speed or Whipple or tyler crocket or somebody of their caliber do some HP upgrades,,, could probably get about 500 our of the mag motor for less than 5 grand and be 75 hp and a few grand ahead..

Any thoughts or considerations about this, would love some input.. Thanks Chris..

Also has anyone modified a regular mag motor and what were your results..

Do a search here you should get a few hits as this has been discussed before.

cam and ecu are the only difference

chris put this topic on general discussions it will get more hits . did you get any info from these engine builder about upgrades and if you can run 89 octane fuel ?

Chris,

The 496 Mag has a steel crank and the HO has a forged crank. Otherwise Muffman is correct, cam and ecu are the only other difference. The cam is upgrade is $550.00 and the ECM is $1600.00 Cheeper to cahnge the parts yourself and pick up the extra 50 HP.

Lean on the dealer a bit more...you should be able to upgrade for around 3 grand and wind up with a better "base engine" for future mods. Also, you can keep your warranty intact for at least a year, more if you go for the extended and do not modify. Depends on what your priorities are...only you know that.

Best of luck,

G-

Not true. The HO originally had a forged crank (very early), but now both models have a cast crank and cast pistons. Even the 525hp HP3 motor has a cast crank.

If we are talking about a complete package here (drive and engine) you will get the Bravo One X drive with the HO version instead of the standard Bravo One.

This bugs the begeebers out of me. Why are there so many opinions about these engines ? And if OSO is such a great place to get high performance boat information and has such an impact on the high performance boating industry, why doesn't someone from Merc. come on here and answer this question.

Based on a couple of posts here that contradict each other, you do not really know what is the correct answer.

I am not an engine guy per say, but the 525 HP, or the
HP3, with a cast crank.....that is difficult to believe. Forged is stronger due to work hardening in the forging process and has better grain alignment for better stress distribution for an overall stronger more durable crank shaft. My 500 HP's had forged cranks.

I agree you should lean on the dealer more. $5,000 sounds a little steep to me. Remember you are in control, it's your money. Make him earn it.

Hey Chris,
We've been working with these engines for over two years now. I can tell you that none of the newer 496HO engines has forged cranks. Everything is the same except cam and ecu programing. Sounds like the dealer is hitting you hard for the upgrade. Save your money our aluminum heads will be available in March and our new cams in April. They will give you 500+ HP with ecu reprogram. Just get the XZ drive minimum.
Good Luck Raylar:cool:

GM Powertrain thinks that forged cranks are unnecessary because the 496 motors are internally balanced and thus create less stress on the crank. I personally would much rather have the forged crank, but it's not my decision.

Go to this link for all of the specs on all three 496's. You'll see that they all have cast cranks and pistons.


496:
http://www.gm.com/automotive/gmpower...d_brochure.pdf

496HO:
http://www.gm.com/automotive/gmpower...p_brochure.pdf

496 HP3:
http://www.gm.com/automotive/gmpower...3_brochure.pdf

Unfortunately, the 496HO brochure was not properly updated when the crank change was made. You'll notice on pg. 2 that the crank is said to be "nodular iron" (cast) whereas pg. 4 says it's forged. The brochure for the other two motors clearly say the crank is cast.

Here,s my reserch on this topic. Called mercruiser they said all 496HO,s have forged cranks. Then I went to mercruiser parts.com and broke down the crank assembly. They show a part# change on the crank on mag. and HO plus a large price increase. I also e-mailed parts at merc. asking if 496HO had a forged crank and he said forged. The brochures are confusing and this is just my reserch.

The confusion continues.

Thanks for the info guys,, although there is still some confusion.

I think w/ the extra tourqe the 496 makes over the 502 the extra compression would require that with any modifications the 496 is going to be on the edge of deto. and would most likely require mid-grade or probably super..

IF it's only a cam and ECU then the H.O. Is a rip off..

Chris, I noticed your looking at a 288 sun. I have a 2002 mid-cabin288. I was having same problems deciding on engines I ended up with 496HO. I also considered the 496 mag. and 6.2 then put on whipple charge, this conbination is the lightest and cheapest HP.

Raylar,Are you able to re-program the new 555ecu?

I think you have to go to Whipple to re-program the 555 ECU. I have read that they have exclusive rights at this time.

Fuelish Pleasures you are correct on the reprogram, and i too have seen many confusing statements on the forged crank issue. The last of which was in HotBoat mag where the stern-drive Q&A guy answered a "wanna whipple it" question, and he said the HO had the forged BUT even the mag witht eh steel was stout enough to take up to 5psi pressure and hold up well.

I guess it will be hard to know until a couple of more years go by and tried and true feedback starts to roll in from the users...

For me it would be as recommended above, work the dealer; get the HO and don't screw with the warranty...