Re: New 496 aluminum heads
 

Hydrocruiser:
The 496 engine is really unlike anything before in the bigblock family. First the long 4-3/8" stroke coupled with the long 6.7" rod and a piston with a .080 pin offset to the power side give this motor a chance to make a lot more push on the crankshaft over more degrees of the powerstroke of this engine. This in turn creates more torque than even an equivalent displacement shorter stroke big block like the 502. The big limiting factors we found almost two years ago after lots of tests and modification were the cylinder heads and the factory intake manifold. These two parts of the engine were never designed or intended to produce big power over 3500 rpms and their original intended use in trucks did not require it.Now that parts such as our heads and intake manifold are here the horsepower and the real workhorse torque are here in a big way!
We are completing dyno tests over the last month where we have seen 525HP and over 600ft.lbs. of torque on dyno pulls with just a head and manifold change. Don't let anybody tell you otherwise, the new modified 496's will be the efi engine of choice in the next few years, no problem!
Ray @ Raylar

Re: New 496 aluminum heads
 

Anymore news regarding the 496MAG? I'm looking to get more HP out of a set of twins.

Re: New 496 aluminum heads
 

You can turn your 496Mags into 525 HP engines with our standard 103 kit and an ECM reprogram. There have been many 496MAG owners who have done this covnversion over the last two years. Call Us.

Regards,

Ray @Raylar

Re: New 496 aluminum heads
 

Ray I'm still looking into see if my hull can handle the speeds this upgrade will produce. Also will my Bravo drives handle the HP increase and still remain reliable?

Well the research I've done shows that my hull won't handle the speeds that 525hp will produce, but somewhere in the regards to 425-450hp it will and this will also allow my Bravo drives to live alot longer. Is there any mods or part of your kit that will just give me 75-100hp gain?

Not being a hull expert, I don't know about the power levels on a Boss 302, but i did check and I see that the HP525 engines were an option on that hull and usually I would think Baja did some research before offering that option.

As for lower levels of power for your 496 Mags, I would recommend our camshaft and an intake manifold first with a reprogram of your mag ECM up to HO specs. that should give you about 475-485HP with about 200 rpms more top rpm. Let me know if we can help. (866) 496-8181

Best Regards,
Ray @ Raylar

The research I've done regarding the hull is anything over 79-80mph the hull gets really loose and starts to chine walk. This comes from a friend that had a 302 with hp525's in it.

Regarding the intake and cam will the heads flow well enough to skip the complete kit being I already will have the motors out I don't wanna pay twice to pull them. I was also leaning towards just leaving the stock manifold and doing your cam and head, but being I don't know much about the 496's and leaning more on your knowledge and experience regarding this to help me make my decision. Most of the techs I know don't have much if any experience playing with the 496's and sorta are leaving it up to me to make this decision. Thanks for your help.

How should I really upgrade a marine high performance engine??
 

NO, If you are going to do anything just remember that any high performance engine is an air pump, restrict or impair the air flow at any point in the air flow tract and you will limit the air pumps total air flow and that restriction in an engine air pump will restrict the power or the increase in power.
We developed a new aluminum head for the 496 because we knew the factory iron heads were not flowing air well, were not really upgradeable and could not make more power without a substaintial increase in their flow. When we finished the head we discovered that the stock intake could not flow the increase the new heads were flowing, so we had to develop a new manifold. After we created a new manifold we realized with testing that a new camshaft would also be needed to feed the whole engine with the new airflow the heads and intake could deliver.
So when you just make a manifold or cam change you won't see the increased airflow or the increase in power that goes along with it. Likewise, just change the cam, or the heads only, you will limit the airflow increase needed for more real power. You really need to wait until you can get the total system needed for the airflow that will provide a good increase in power.
This is why the Raylar kit makes a hundred horsepower increase @525HP on a 496 engine, not the individual increases of just single part additions.
When your 496 is then at that level of increased airflow and power you can then add a good exhaust header and take the horsepower up to 565-570 hp because the engine can benefit from the increased airflow the headers will add.
Enjoy your stock 496's, add headers if you wish for now for a small increase in power 30-40hp and then add the Raylar 103 kit and you'll see a real 100HP addtional increase for your 496. Any other single or limited parts addtions will not net you a respectable increase in power to offset the cost and time cost (labor) of the individual part upgrade or change!
As for chine walking and handling issues created by more power, that will vary from hull type to hull type and size and in most cases most of that issue can be solved with prop changes and hull bottom massaging or repairs.
I think its important here to also mention that pulling an engine like the 496 out of most boats with Bravo drives is not that big of a project if you have the time, about 2-3 hours out, 2-3 hours in with a lift and proper tools and work space and another set of hands and eyes. This is the proper and a quicker way to do any major engine changes and protect the boat and interior from damage and uneeded wear and tear , especially to interiors and topside finishes.
This is about the only way most good service shops will attempt to make any major engine repairs or upgrades to any inboard engines in high performance boats.

Hope this helps with your "Research".

Best Regards,
Ray @ Raylar

When I was at Innovation marine I ported a set of factory heads that made a touch under 600 hp at 5700 rpm. The intake was stock with some cnc machining at the flanges. The factory heads with correct porting can make descent power.

Jimv:

Understand you may have reworked a set of iron heads for more flow, but our heads and a much smaller cam make with our 106 kit just over 620HP at 5200rpms and a lot more midrange torque from 3500rpm to 4200rpms on a 496.
This is where the big blocks will see much better hours of reliable usage under 5400rpms and the big cams that move peakpower on these motors up to 5700rpms are a lot more prone to reversion with the larger durations and the idles tend to get a little rough and require more than 650 rpms to stay lit which is hard on Bravo drives when shifting.
Just my opinion, but I say make big power at lower rpms with more torque and you have a better recreational performance marine engine, racing, thats another animal.