My dad and I each bought one of these for 1985 M635s, but he sold his car before it was ever used. Made by Bert Poliakoff, this allows the use of a spin-on Ford 460 V8 screw on filter. This is the version for the cars with the bottom-bolt filter canister.
https://bigcoupe.com/phpBB2/viewtopic.p ... er#p170085
Boxed and ready to go, $120 shipped to you in CONUS via USPS's 'if-it-fits' box.