I'm running a bike that's 43yrs old which has never had the cam chain replaced,plus the cam chain tensioner wasn't properly adjusted when I got the bike

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I'm looking for a good Japanese cam chain(at least 120links), #219H type and a separate rivet-style master link;I have the good Made in USA cam chain rivet tool made by Kent Moore.
I want the standard Japan non-HD chain,just Not made in China.
The more worn a cam chain gets,the more it retards the cam timing;I want to replace that chain for better low-end and improved all-around performance.