KE Headers on 525 EFI
11-21-2018 | 03:54 PM
#11
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From: Cape coral, FL
If I use them mine will have to be made. My gils already use wedges. Heads are .500 taller on exhaust. I have horrible plug access with the gils. Contemplating headers to make that much easier. Not sure how the T&L would be there since these aren’t stock heads
11-21-2018 | 05:01 PM
#12
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From: Chicago, IL; Onekama, MI
FACTORY CMI headers that came on 525s are the issue. CMI makes better products. But the headers that Merc spec’d for the factory package were usually just good enough to last the warranty period. CMI got the bad wrap for such, but it’s 100% Mercury’s fault. CMI wanted to put better headers on there originally but Mercury price/volume pressured them to the lesser product.
11-21-2018 | 05:21 PM
#13
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From: Ft. Worth TX
I recommend Diamond / Bill exhaust and I will tell you why. I have worked on Volvo DPX 600 engines and had a twin app with full CMI headers - one side CMI were leaking as I CHANGED in time. That owner ended up buying at that TIME were KE currently Diamond / Bills exhaust and there was NO Drop in speed or performance period. I know because I drove and maintained the boat every year.
Last edited by BUP; 11-21-2018 at 09:07 PM.
11-21-2018 | 06:30 PM
#14
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From: De.
The K/E Headers will fit the Merc 525efi -
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11-21-2018 | 09:20 PM
#19
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Joined: Mar 2012
Posts: 4,189
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From: Cape coral, FL
agreed at this point. With these heads and I think slightly altered plug angles I had to clearance manifolds and grind a socket down just to do them on a stand. Gonna be doing them in boat now. Sure that’ll be a blast.
11-21-2018 | 11:31 PM
#20
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From: On A Dirt Floor
Endeavor32: Make the beginning of the KE/Diamond tails to the end of the tips 18"-20". 19.5" is ideal. Your welcome. 
---- Collector's Harmonics (includes Intermediate, Muffler , TailPipe) ----
1st Harmonic = 155.2 inches long ... longest with Mufflers and TailPipes
Note: Worst = 116.4 inches long for HP/TQ Loss
2nd Harmonic = 77.6 inches long ... longest recommended with Mufflers
Note: Worst = 58.2 inches long for HP/TQ Loss
3rd Harmonic = 38.8 inches long ... more bottom-end Torque
Note: Worst = 29.1 inches long for HP/TQ Loss
4th Harmonic = 19.4 inches long ... highly recommended , best Torque Curve
5th Harmonic = 9.7 inches long ... reduced Torque , more top-end HP sometimes
6th Harmonic = 4.9 inches long ... reduced Torque , not recommended
---- Collector's Harmonics (includes Intermediate, Muffler , TailPipe) ----
1st Harmonic = 155.2 inches long ... longest with Mufflers and TailPipes
Note: Worst = 116.4 inches long for HP/TQ Loss
2nd Harmonic = 77.6 inches long ... longest recommended with Mufflers
Note: Worst = 58.2 inches long for HP/TQ Loss
3rd Harmonic = 38.8 inches long ... more bottom-end Torque
Note: Worst = 29.1 inches long for HP/TQ Loss
4th Harmonic = 19.4 inches long ... highly recommended , best Torque Curve
5th Harmonic = 9.7 inches long ... reduced Torque , more top-end HP sometimes
6th Harmonic = 4.9 inches long ... reduced Torque , not recommended
Last edited by SB; 11-21-2018 at 11:34 PM.
