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The Simplex 5V 14-24T gear block is OEM.
I got the same block on a 1973 RRA model purchased new.
The original rear spacing would have been 120mm.
When wheels were replaced the OEM block was fitted to the new rear hub.
The thee common rear spacings for road bicycles are 120, 126 and 130.
At the time your bicycle was made 120 was the standard.
If you are unfamiliar with alignment and chainline there is a good presentation at the Sheldon Brown site.
Since the rear spacing has been altered from OEM you would want to check alignment even if you decide to retain the changed spacing.
https://www.sheldonbrown.com/frame-spacing.html
The forum has other members in the Sacramento area. Perhaps one of them could lend a hand if need be...
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