340 in a 1966 valiant, remote oil filter woes

Why -12? That is huge. Your fittings certainly don't look like they are AN -12. Maybe -8? The block holes need to be drilled & tapped for some size of NPT adapters to attach the AN hoses to. I do not know the exact sizes, as I'm am not sitting here looking at an LA engine block, but it's needs nothing nearly as large as an AN -12 (which is for a hose with about 3/4" I.D.).