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Discussion Starter · #1 ·
Here's something I haven't seen addressed, but looking at exhausts, I have a question. The '68 and '69 exhausts have a flare at the end of the pipe where they bolt to the head, and use long split collars. The '70-'73 exhausts have a fixed sleeve around the end of the pipes at the head end, and use short split collars. Is using a late model exhaust on an early model (and vice versa) just a matter of using the correct length split collars, or are there other differences such as exhaust stud length and which era finned clamp you use?
 

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Early heads had smaller studs on the exhaust. I've been able to put different sets on using the appropriate matching collars.
 

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Discussion Starter · #3 ·
Do you mean smaller, or shorter? Mine's a '69, so it has the "normal" diameter studs.
 

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Smaller diameter, 6mm vs 8mm ..... if memory serves me correctly. I think your 69 was updated with the larger diameter.

The parts manual shows the serial number breakdowns.
 

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Discussion Starter · #6 ·
Ok, I did a little parts diagram fishing and came up with this...

Up to serial number CL350E-2078009, the exhaust studs are 8x56, and after that number, they are 8x58. Since I have more than 2mm thread showing on my '69 exhaust, I will assume that a later "sleeved" exhaust will bolt on ok if I use the shorter split collars, right?
 

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Discussion Starter · #7 ·
Thought I'd provide an update to answer the question for anyone else who has wondered about this. I bought a set of CB headers that came off a '71 model that have the wide sleeve at the head connection. I bought a set of the matching "short" split collars to go with the later model pipes, and everything bolted up just as it should. Studs were plenty long enough, too. Conversely, if you want to run the early flanged pipes on a later-model 350, all you need are the longer split collars.

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The change to the Collar at the Exhaust Flange was to improve durability.
The Original design had a tendenciy to SPLIT and the collar was a reinforcement of the weak point.
 
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