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525 old gen/new gen

Old 01-07-2021, 09:36 AM
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Default 525 old gen/new gen

Looking to buy a 525 boat. How can I determine without taking a motor apart weather or not it has the composite head gaskets or the later MLS gaskets?
Also is there a way to tell if they are the good or bad headers or not? I know that with the early 500efi headers if the outer tube goes all the way to the flange they were the ones that cracked, the later ones that were revised the outer tube stopped about an inch or so before the flange and they were not supposed to crack. Was just wondering if that was the scenario with the 525 headers as well, or if it was just simply wall thickness.
Thanks for your help
Craig
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Old 01-07-2021, 09:55 AM
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The later design on the CMI 525 headers is referred to as cool collar, if the head gasket is MLS you should be able to see one or two of the rivets that hold the layers together, possibly front lower by #1 plug
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Old 01-07-2021, 11:16 AM
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Thank you, I have a mechanic looking at the boat as we speak and was wondering if it has the ARP head bolts does it mean that it has the MLS head gaskets as well
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Old 01-07-2021, 11:20 AM
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Originally Posted by cprperformance View Post
Thank you, I have a mechanic looking at the boat as we speak and was wondering if it has the ARP head bolts does it mean that it has the MLS head gaskets as well
No
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Old 01-07-2021, 12:03 PM
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Originally Posted by cprperformance View Post
Thank you, I have a mechanic looking at the boat as we speak and was wondering if it has the ARP head bolts does it mean that it has the MLS head gaskets as well
That means its been apart..............which could be good or bad, and scanned engine hours ?
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Old 01-07-2021, 10:53 PM
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I read somewhere on here that the updated version of the 525 had MLS head gaskets and ARP head bolts.
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Old 01-07-2021, 11:03 PM
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Just got some pics back and it does have the ARP head bolts and the MLS gaskets



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Old 01-07-2021, 11:21 PM
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Who tuned the ecm? 525ís stock donít rev past 5400
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Old 01-08-2021, 09:07 AM
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those engine have had a pretty easy life, are the wires in place from the factory, meaning sealed not been apart
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Old 01-08-2021, 09:29 AM
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I cant tell you that. I have had a real tough time dealing with these guys on this boat, keep in mind I am in Northern MI and the boat is in TX. I am an auto mechanic myself, it gets real frustrating trying to get answers to simple questions out of somebody that knows nothing! Its been a week just to find out if it has MLS gaskets and ARP bolts. I guess I'm just going to have to fly down there.
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