525 Header fix
 

A friend is considering buying a pair of used 525 long blocks. The engines have no headers, It seems he will end up spending more on the new headers/tails if he buys them new than the engines themselves! Gen X headers are like 14K with tail pipes! WOW........ I know the bolt pattern is different than regular heads, so since the "525 problem", has anyone made a fix for the problem??... like an adapter or something so you can use old style headers If not, are there any brands that make "reasonably priced" headers for these engines? OR, does anyone have 2 used sets they are looking to part with? Thanks in advance.

Kev, redrill the heads and use std headers/tails. There's a jig that can be bought or rented to do this.

If he goes stainless marine they have the jig.

Id sell those heads to another member who already has the headers, buy AFR, Brodix ect. that flow a bunch better and be done with it, then put e-tops or something else on it, JMO

+1

Replaced my CMIs with SM this season. So far, so good.

Thats what I would do ...

I have 2 seasons on my SM headers with zero problems after 3-4 years of issues with the CMI's. I had them painted blue to match the motor...looks great.

What year did Mercury revise the headers to fix the issue? Or is it all 525's?

I think the headers that have the outer tubes welded directly to the flange are the bad ones. I had the newer style on my 2005 model motor. I just replaced mine after 220 hours and they tested OK. No headers are going to last forever though.

I just put on the hardin marine headers, heaver and they are not CMI

i had a set of those, very nice well built units. They did seem heavy for how big they were which leads me to believe they were pretty beefy . . . .

from what everybody says 4-6 yrs on headers and there junk.buy something that last and last.stainless marine.