525efi
 

Whats the cam spec for a 2005 525efi .?
What would be a suitable upgrade ?

I do not know what the specs are, but i do know that the intake is pretty close to its maximum flow capability already, so a cam change might not gain you much for all the work.

Now if you change a bunch of other things around at the same time, you can gain more power, probably closer to 600 hp.

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What would you suggest ?Heads off after full bottom end rebuild.

Your biggest problem will be the ecm reprogramming. There really isn't anyone doing it. Your cheapest bet would be to remove the ecm and replace it with a Mefi IV ecm and harness. This can be easily tuned by several people, including me. This is what Whipple does with their supercharger kits for the 525. An ecm and harness will run you approx. $1200. You will not be able to change the cam without doing some programming. Good luck.
Eddie

Tyler Crockett can reprogram you stock ecm. That would pick up about 35 hp.

He can do the Mefi, but not the ecm in the 525 efi.

I disagree

The only person in the US that can get into the pcm555 controllers is Dustin Whipple. He may start to do the 525 ecms, like he is doing the 600, 700, etc. At this point, he is replacing the ecm on the 525 with a Mefi IV in the 525 efi Whipple kit.
Eddie

Ecm?
 

What motor does that ecm come from ?
is there no gain from working the heads ?

The cam is a Crane 741 that is ground on a 114 lobe sep.

Here are the regular 741 specs http://www.cranecams.com/index.php?s...41&lvl=2&prt=5

Which ecm are you referring to? The Mefi IV or the 555. Merc. never used the Mefi IV. They used the I, II, and III. Volvo used the IV on a few engines. It is an excellent ecm. They use the 555 on several engines.
As for the heads, there is only a little to gain with some port work. The restriction is the intake. If you changed the intake, then some head work will make quite a bit of improvement. I replace quite a few of the 500 and 525 intakes with a setup from Holley. It is a single plane intake with the injector bosses casted in, fuel rails, injectors, 2000 cfm throttle body, sensors, etc. for about $2500. It is worth every penny. Edelbrock makes a similar setup as well.
With one of the above intakes, a bump in compression, cam change, and a little head work, you can make over 600 hp easily.

Here are a few pics of the Holley intake setup.
Eddie