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-   -   Cheap 496 mag upgrades (375hp) (https://www.offshoreonly.com/forums/general-q/245147-cheap-496-mag-upgrades-375hp.html)

s-cam 01-09-2011 09:33 PM

Couple questions since i am in the same situation.
#1- what order would you start to do the mods (cam and pcm, then exhaust or the other way around)

#2- would you recommend the raylar 103 cam or the stock 496HO cam ?

Any gains in the stock heads to be had? slight port and polish or is it a total waste of time?

I have a Baja Outlaw 25 with 496 mag and was planning on doing cam and pcm, then headers, then prop work ( I am leaving prop til last due to the variations of altitude that i run on for lakes) Oh and doing work to the bottom side of the boat but thats a whole other post....

Sheldon

Centsless 01-09-2011 09:46 PM

i run a 496 HO
took the K&N off and used a larger flame arester
installed CMI ETop Headers
and put a 26 labbed 4Blade prop
went from an average speed of 62 mph
to an average of 68 mph all gps speeds on my laveycraft
also boosted the fuel pressure 5 PSI to maintain air fuel ratio with the extra scavenging of the headers
and im not doing anymore to this motor......
cheaper to buy a whole new hull with the power i want than it is to modify

Wet-N-Wild 01-09-2011 10:21 PM


Originally Posted by Centsless (Post 3293044)
i run a 496 HO
took the K&N off and used a larger flame arester
installed CMI ETop Headers
and put a 26 labbed 4Blade prop
went from an average speed of 62 mph
to an average of 68 mph all gps speeds on my laveycraft
also boosted the fuel pressure 5 PSI to maintain air fuel ratio with the extra scavenging of the headers
and im not doing anymore to this motor......
cheaper to buy a whole new hull with the power i want than it is to modify

WOW!!! SO MUCH GREAT INFO IN THIS TOPIC. NO I REALLY DON'T KNOW WHAT TO TRY OR WHERE TO START. BY THE LOOKS OF IT I'M BETTER OFF KEEPING MY MONEY IN MY POCKET AND WAITING TILL I HAVE ENOUGH TO TOTALLY REBUILD MY 496HO AND ADD A WHIPPLE. THANKS AGAIN FOR ALL THE INFO GUYS:)

Rage 01-10-2011 07:43 AM


Originally Posted by Centsless (Post 3293044)
i run a 496 HO
took the K&N off and used a larger flame arester
installed CMI ETop Headers
and put a 26 labbed 4Blade prop
went from an average speed of 62 mph
to an average of 68 mph all gps speeds on my laveycraft
also boosted the fuel pressure 5 PSI to maintain air fuel ratio with the extra scavenging of the headers
and im not doing anymore to this motor......
cheaper to buy a whole new hull with the power i want than it is to modify

Curious, what was the first prop and the rpm you ran for the 62 mph and what is the rpm you run at now for the 68 mph?

thirdchildhood 01-10-2011 08:03 AM


Originally Posted by Rage (Post 3293182)
Curious, what was the first prop and the rpm you ran for the 62 mph and what is the rpm you run at now for the 68 mph?

Yeah, one thing at a time. The flame arrester did nothing unless someone had put a ridiculously small one on there and......6 mph from exhaust upgrade? It's not that easy...............

Keith Atlanta 01-10-2011 09:12 AM


Originally Posted by Centsless (Post 3293044)
i run a 496 HO
took the K&N off and used a larger flame arester
installed CMI ETop Headers
and put a 26 labbed 4Blade prop
went from an average speed of 62 mph
to an average of 68 mph all gps speeds on my laveycraft
also boosted the fuel pressure 5 PSI to maintain air fuel ratio with the extra scavenging of the headers
and im not doing anymore to this motor......
cheaper to buy a whole new hull with the power i want than it is to modify

The K&N just plain sucks - my boat went 1-2 MPH slower.

5PSI? Just for headers? That would drown a 496, does you transom look like a coal mine?

Centsless 01-10-2011 09:45 AM


Originally Posted by Rage (Post 3293182)
Curious, what was the first prop and the rpm you ran for the 62 mph and what is the rpm you run at now for the 68 mph?

the boat when i bought it was underproped the tack read full rpm but it wasnt a good guage i have since replaced the guage the prop that came with was a 22 bravo 4 blade laveys in my size with a 496 ho come stock with a 24 bravo 4 blade

Centsless 01-10-2011 09:47 AM


Originally Posted by thirdchildhood (Post 3293194)
Yeah, one thing at a time. The flame arrester did nothing unless someone had put a ridiculously small one on there and......6 mph from exhaust upgrade? It's not that easy...............

exhaust , and labbed prop..... the added fuel pressure is only to protect the mixture ratio

Centsless 01-10-2011 09:58 AM


Originally Posted by Keith Atlanta (Post 3293263)
The K&N just plain sucks - my boat went 1-2 MPH slower.

5PSI? Just for headers? That would drown a 496, does you transom look like a coal mine?

it was only the delivery pressure nothing else.... and it does soot up in the early part of the season .....but it beats a roached engine all to hell

Centsless 01-10-2011 10:05 AM

now having said all this......... the headers most likely only gave me 20 to 30 more hp perhaps a bit more
this allowed me to spin a larger prop but it need to be labbed.....
my mechanic and i did touch 70 once with a labbed 3 blade
but the overall handling characteristics were horrible
back to the 4 blade.....and the cost averaged out to about $1000 per mph for the purchase and work done


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