I always install the pipes onto the exhaust studs loosely.
Barely starting the nuts.
Install the collector then tighten all the exhaust nuts.
I use the copper locknuts.
Those won't seize to the stud, they are 12mm so the nut flats don't hit the welds on the flanges.
They have that undercut that needs to face the flange.
That also helps with flange weld clearance.
After your run the engine enough to put some decent heat into the heads, shut it off,
let it cool then re tighten the exhaust nuts.
Sometimes take 2-3 heat cycles doing this until the nuts stay tight.
If you don't do it like this, you'll pop an exhaust gasket in short order......
_________________
Gary
Turbo VW Sand Racer
Polaris Ranger
"If you don't run into the Devil every once in awhile, you must be going in the same direction!"
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