Is there any advantage to one of those right angle oil filter adapters if you don't have headers?

They create another possible leak point and likley create at least a little flow restriction. If you don't need it for clearance I'd take a pass.

ALL Chrysler 5th Ave, Dodge Diplomat and Plymouth Gran Fury cars used this adapter since they had PREcatalytic converters. There wasnt enough space to fit the filter in the regular way. I say if it was good enough for the Police, it must be durable for a street car. It DOES allow you to use a larger filter than the usual size. A bodies are limited with the torsion bar in the way. B and E, as well as Aspen/Volare cars would probably be okay without the adapter.

Would be nice with a straight up and down filter so you don't make such a mess doing an oil change on my 440. I thought about doing a remote oil filter mount that relocates the oil filter with a hose instead of a 90* adapter. This way I can put it where I want and install an in-line oil cooler as well.