Word to the wise, Drain em down after every run. Also, pull your headers off at the end of every season. Have them pressure checked and heat the inside of the tubes with a torch if you have too....it makes the leaks come out more....

In the past 3 years I've had to fix leaks 2 times of which there were 1-2 leaks in 2 out of 4 headers.

It's a yearly ritual.....

Just unscrew the little blue draincox right? Also, converting to a dry exhaust will prevent bad things from happening???

Yup, If you have a little drain then that makes things easier! Only drain the header though, not the whole motor. It's not fail safe but if you have a tiny leak in one of the header pipes it well keep it from draining down and back into the motor.

Switching to a dry exhaust wont help any....unless the exhaust isn't water jacketed....kind of like a header in a car or drag car or garvey lake boat etc...

KE, KE, KE, KE, I'm telling you, it's the way to go!
Dean

Could you re-explain? I don't speak Spanish!!!

[QUOTE=Panther;2147746]Word to the wise, Drain em down after every run. Also, pull your headers off at the end of every season. Have them pressure checked and heat the inside of the tubes with a torch if you have too..

Man if I did that I'd never hear the end of it from my girlfriend about how anal I am. Don't even go there guys, I can never make her understand. I thought CMI was the way to go but after this thread, count me out!

Had CMI's on my last motor. Found out I had a leak after the fact. Blown motor! ,Cracked Block!, Sent them to CMI for testing and repair. Port side it great starbord is junk and can't be repaired. They claim they only last 7 years. They are 7 years old. any one got a good starboard for sale? or want to buy mine with tail pipes? Just got a set of KE's

I had a header on one of my 525's start to discolor and had it replaced before it could take a dive. But I was told that because of the funky bolt pattern on the heads that the CMI is the only one that will fit because it's made just for that motor. Is someone else making a header now that will fit?

This is what I heard as well, that Mercury changed the bolt pattern from what has been GM standard for a bazzillion years and as a result the CMI is the only option - anyone got confirmation either way??

Just for information, most any stainless headers with a big block standard exhaust bolt pattern can be redrilled to match the Mercury Racing exhaust pattern. The reason Mercury changed was that there are a few bolts on the headers that are a ***** to install and remove on the standard chevy pattern with stainless header flanges. One of the contributors to stainless header leakage and cracking also comes from movement and vibration which is greatly increase with long tails such as in staggered packages, etc. Get good supports made for those puppies! I think with the cost of motors you stainless header owners at the beginning of each season should rig a simple pressure tester fitting and hit them with let's say 50 psi air pressure, cap the pressure and watch for leakage. Got leaks! Don't run'em until repaired! An Oz. of prevention worth a pound of cure! Seems I heard that somewhere before?

Regards,
Ray @ Raylar