I have an OER #9794252 shifter cable in my '68 for a couple years now. Yes, very tight bends as shown above. No failures. Does shifter and/or transmission seem free when going through the gears by hand?
I'm generally not a fan of OER's quality and try to avoid their products. I ordered cable from NPD without knowing the brand but fit was good and part trouble free.

I have a couple used GM cables if you would like to try one? Would send one if you pay the freight. (I'm guessing $10 for USPS.) The little boot at the transmission end is long gone but they are otherwise useable. PM me and let me know.