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merc 525sc head + cam upgrade!!

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Old 10-25-2011, 06:26 PM
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Default merc 525sc head + cam upgrade!!

I want to gain 100 hp with my 525sc stock engine.

Does he have anyone that he can suggest a good aluminum head that i can fit on this engine???

I want to mach the smaller 177 blower pulley (2,850'') and a good cam like Crane 731 or bether (anny cam suggest???) with a new aluminum head without chiller (no space for it).

What about the Eldebrock Performer rpm marine head????

Here are the spec:

Heavy-duty, 1.89" Inconel exhaust valves provide added durability for marine applications
Hard anodized black to protect the aluminum in the harsh marine environment
Sold with valves only to allow for valve spring choices
Match with an Edelbrock Performer RPM manifold, Performer Series 750 cfm marine carb and Performer RPM cam for proven performance
Smaller-than-stock 11/32" valve stems promote excellent flow and lighter valve weight



Combustion chamber volume 118cc
Intake runner volume 315cc
Exhaust runner volume 110cc
Intake valve diameter 2.25"
Exhaust valve diameter 1.89"
Valve stem diameter 11/32"
Valve guides Manganese bronze
Deck thickness 9/16"
Valve spring diameter Springs Not Included
Valve spring maximum lift Springs Not Included
Rocker stud 7/16"
Guideplate Hardened steel
Pushrod diameter 3/8"
Valve angle 26°
Exhaust port location Stock
Spark plug fitment 14mm x 3/4 reach, gasket seat
Made In USA


Does it is possible to get this aprox 100 hp with that upgrade More boost, aluminum head and cam upgrade???
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Old 10-25-2011, 07:20 PM
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I run the 177s on 454s with 9.5:1 compression, 731 cam and edelbrock rect heads, 1050 dom carbs. I run around 6psi with the 3.25" pulleys. I estimate the combo in the 625-650 hp range. Works nice. The higher compression crutches up the 177 blower which is a bit small for a 454.
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Old 10-26-2011, 06:43 AM
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What is your timing with 9:5 comp and 6lb of boost?
Also do you run with a chiller?
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Old 10-26-2011, 06:55 AM
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Im running a hyd roller cam, 8# pulley, crane gold roller rockers and a 1050 domain. id guess im in the high 500hp range. I don't think a 750 will be enough carb
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Old 10-26-2011, 07:09 AM
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Originally Posted by Drock78
Im running a hyd roller cam, 8# pulley, crane gold roller rockers and a 1050 domain. id guess im in the high 500hp range. I don't think a 750 will be enough carb


I run with the same carb... do you have chiller with 8lb of boost?
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Old 10-26-2011, 07:29 AM
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Call Bob Madara at Marine Kinetics http://www.marinekineticsonline.com/

He has a good package for these engines. Should be able to get the power increase your looking for and he grinds his own cams...very knowledgeable guy.
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Old 10-26-2011, 08:06 AM
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I X2 Bob Madara! If you want an aluminum head go with the AFR 265 Oval or maybe the 290 Oval. They are both MUCH better than the Edelbrock heads. Either way call Bob he'll set you up with the right cam and head for your combo and goals. Here is his number 585-654-8583
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Old 10-26-2011, 10:34 AM
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Originally Posted by supermx96
What is your timing with 9:5 comp and 6lb of boost?
Also do you run with a chiller?
No chiller, 30* all in with V6 tbolt modules, 11.8 afr wide open. Aluminum heads help.
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Old 10-26-2011, 11:11 AM
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The AFR heads do seem to be very good. The stock intake is rectangle port on a 525sc. Blue Thunder, I am curious what exhaust temps are running with 30 degrees total timing on your boat. I had some 2.85 splined pulleys that were for the Merc 177 blower and I didnt like the way they fit the shaft, so I changed the shaft out to the automotive one and it uses a keyway so you can get pulleys from summit or Jegs.
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Old 10-26-2011, 11:39 AM
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Good call on rec port intake. The AFR's the I mentioned won't work for that application. Either way give Bob a call, he'll make sure you do it right the first time.
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