The two slant 6's I had were oil burners---but, they were both bought used, and probably abused
As long as I threw a quart in every now and then, they ran.
I think that one of the reasons US manufacturers stopped making in-line 6 cylinders was, they ran forever. The one in my Jeep is just getting broken in at 120K miles
My family had very good luck with the two 318s we owned. 68 Fury III, posi rear end, thing was a tank in the snow. Sold it at 144K, they guy who bought it took it all the way to almost 300K before the body rotted away. 69 Coronet, too. Gave it to my cousin and she ran it into the ground. Neither one ever used a drop of oil between changes.