A little slack in those shaft pivot holes is a good thing. Too tight, and they'll seize up again. Unless there's a noticeable exhaust noise from the shaft holes with the engine running, sloppy is good. Since that flapper valve and shaft is exposed to exhaust gas at 1500 degrees F. or more at times, getting energetic with an acetylene torch while freeing things up isn't going to damage anything. Ditto for getting the bolts loose- - - -close to red hot is OK.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!