I'm pushing 300hrs on my 2004/5 525s. They run fine and I'm hoping they continue to do so. Lots of this stuff scares me. I will probably pull the valve covers and check the rockers and may have the headers tested. Otherwise I will probably have to run 'em 'til they break due to budget constrictions. May not be smart but I don't have a choice. I've talked to Eddie in the past and that's who I'll call when something goes.

We also had to replace the Headers and are using the GenX hearders. So far so good, we'll have to see how they hold up vers the older style CMI Merc headers.

Just checked over my 04 525's last week. Headers and all checked out well
with 170 hours. Thank you Eddie for explained how to check the headers etc.
I was expecting a problem but as of now all looks well.

I pressure test my headers like this. Put about 40 psi of air pressure in the water jacket and submerge them in water. Then wait and watch for even the tiniest bubbles. These tested good.

Awesome that looks easy enouch... Good info.

With 300 hrs., I would at least change the springs, retainers, locks and seals in addition to checking the rockers and headers.

Eddie

Eddie dont have your number if you get some time give me a call
Frank
321 693-0023

I always catch him by the # in his avatar

Thanks

So from the data we have put together it looks like there is 30 / 35 HP differance between a bone stock 525 and one with the ECM RPM turned up. It looks like the sweet spot on the RPM's is 5500 / 5600 rpm about 150 more then stock setting from Merc . As a few ppl have also found the fuel octane between 89 / 93 doesnt seem to make a differance from our tests at least on the dyno as far as HP. With the comp at 9.0.1 seems like the 89 run just fine.

This have be a very informative thread with great input from alot of ppl. Specail thanks to Eddie for taking the time to anwser so many question and all of his first hand knowledge