Those "threaded compression sleeve" type fittings are getting tougher to come by - especially when incorporated into a flex line, as on the 270.

Your post did not show the return line, but your pics of the feed line look exactly like the one on a GMC CCKW. Assuming it is the same, you could try searching for PN 2137793.

I looked for one several years ago, but could not find any available domestically, so I ordered one from these guys, in NL.

Oil Filter Lines

They don't list them explicitly on their website, but if you send them an email asking what you need, they should be able to accommodate you. The line came in a set with both the feed and return.

Best Regards...