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Performance set up

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stugots1992

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"Can anyone give me a good hea

"Can anyone give me a good heads/cam/intake/carb set up, im running a mid 90's 350 magnum thats rated around 260-270hp now but I want a little more. Being a car guy I know what I can gain from this.. I have not had to experiment with marine apps before so if anybody has a good set-up they recomend or have done than throw some numbers my way... I know hp/torque is different from street to water, the hp isnt going to get more speed blah blah blah, thats why I am asking for someone who has had a killer set-up for a 350 mag that wants to share.."
 
"[i]Being a car guy I know[/i]

"Being a car guy I know
that street performing 350's make all their power above 5000 rpm.

Being a boat guy, I know that marine engines never turn that fast.
Which is why 383's and big blocks are required for noticeable gains.

I know hp/torque is different from street to water
It's not different at all, and therein lies the problem,
Torque X RPM / 5252 = HP
You need RPM
In a Camaro..no problem, just build the mouse for 7000 rpm
But that's not an option in a boat.

I want a little more
I'd focus on the prop first.. a nice efficient stainless prop if you don't already have that

If your motor already has Vortec heads, you have good heads already. Cam and intake swaps aren't going to do anything for you at 4500 rpm. }"
 
What is the max WOT you get no

What is the max WOT you get now? What prop are you running; diameter and pitch? SS or aluminum? Is the hull clean ans slick or dull?
 
"(ENGINE set up,lets stick

"(ENGINE set up,lets stick to that) I have done the prop thing already.. thats like putting a different gear in a car and not enough motor or an incorrect set-up to do anything with it.. trust me i have already been down this road, props just make it plane slower or faster, throws the r's all around and no major difference... I will match a prop when I get some more power twist'n it.... OK what is a good size after market cam i could buy that would increase power for me here?????????? thats all i want to know. heads/carb and intake are taken care of already.."
 
"forget about fellas, I got an

"forget about fellas, I got an email from a guy that saw my post and has actually DONE IT and has a good set up.. he didnt want to "dick slap" with you guys..

Thanks anyway"
 
"A big lumpy cam will make it

"A big lumpy cam will make it go real good until the valve overlap causes it to suck a big mouthful of water up the exhaust, goodbye engine. Marine cams are designed to help prevent this, don't fool around with it."
 
"that's the spirit...
&#3

"that's the spirit...
"I have a fix, but I'm not going to tell you about it"
I guess some people feel insecure and need to control their own threads to the point where it defeats the whole purpose of the board.

Can only hope he's being dishonest and actually learned something here about the rpm limitations of a marine engine. "
 
"My fave way of going faster i

"My fave way of going faster is to look for a smaller hull.

No matter how much you tweak a 350, there's always some kid in a 13' voodoo with 70HP flying past you with his bug eating grin..."
 
"LOLOLOL I like that HY Stat !

"LOLOLOL I like that HY Stat ! And you are so right on that! If you have any suggestions for me please share...Im going to attempt to convert an '81 350 that came out of a camaro. It was rebuilt and has about 50k on it. I paid $50. for it from a close friend.This eng is for a '86 Bayliner2560 that had a volvo AQ260A.I dont have alot of money but I look for good deals in parts and acsessories.I have so far a pair of volvo exhaust manifolds,got them for free! obtained a used fuel pump off a rebuilt 260 eng that needs alittle cleaning.What is needed to make a tru conversion?I have gotten alot of discouraging remarks but is it that hard to do this? I installed a FWC merc'260 in my '78 searay 240 sedanbridge by myself and so far,everything runs good but gotta change drive bellow. Pleasa give me the "low down" on eng conversions so I know what to expect. Thanks!"
 
"an 81 Camaro 350 and an 86 ma

"an 81 Camaro 350 and an 86 marine 350 are pretty much identical internally except cam.
Not much to convert the long block. Marine cam, Composite Head gaskets if going in salt or brackish water. Brass core plugs if RWC."
 
"Aren't boat cams similar

"Aren't boat cams similar to RV cams where they produce low RPM torque?

Anyway besides trying to get more HP out of the engine randy needs to consider the limitations of his outdrive as well. Not sure which one he has but if he has an Alpha I think they are only rated for 300hp max. And unless he changes his gearing to 1:32/1 from 1:50/1, he won't notice any speed improvement anyway."
 
"on the issue of upping the pe

"on the issue of upping the performance on the 350 mercruisers without having to make more horsepower at a higher rpm range, instead of having to manipulate a 350 with upper band rpm cams and manifolds, what is wrong with using the 400 cube small block with some later model vortec heads.
i know car guys are making 300 easy horsepower UNDER 5000 rpm and i can buy 400 blocks for $200 all day here and set them up with an engine kit cheap too---- am is there a flaw in these setups?"
 
"Yes, there is a flaw, the rea

"Yes, there is a flaw, the reason why the 400 block was discontinued, cooling. And you have to use the 400 heads with the "steam holes" as the cylinders 3 & 5 and 2 & 4 are siamesed and have no cooling between those cylinders. 400's are OK in street cars where full output is on for short durations but in a boat the motor is working hard 100% of the time and will burn out.

Do the full upgrade on the 350 to 383 with a 212 degree cam and you should make 400 ft/lbs of torque at 3500RPM where a boat needs it and no risk of sucking back water.

Look here http://www.chevymania.com/tech/383.htm"
 
"now that sounds like a good p

"now that sounds like a good package , 400 ft/lbs at 3500 rpm is gobs of torgue at the right rpm--- this is more than the alpha 1 should handle--
the 383 conversion of the 350 is common and straight foreward and in florida cheap , thanks for the link chris!"
 
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