oh boy.. I thought I'd never use my notes again but here I am

and this is just my opinion

DLC is suspose to be for surfaces that reciprocate and rub together, like the lifters Motoguzzi used on my Griso, and failed I might add. DLC is intended to be permenant. Maybe guide rods on automated food packaging equipment would be a good example of a place to use DLC. There are some fancy watches out there that have black cases and bracelets.

DFL is for parts that go together like nuts and bolts, or for a bushing that really isn't very heavily loaded, a bushing for a window crank that is in the doors of our old 911.

I have the spec for helical inserts in a book and I looked up the example

nasm21209

MS21209F4-20L (the L is the designator for dry film lube)

if anyone wants to look up the spec

MS21209 E INSERT SCREW THREAD COARSE FINE SCREW LOCKING

so with using parts that come with DFL, I can save time and ensure my assembly has nuts, screws and inserts that come lubricated

I don't think there is anything wrong with using DFL on cam lobes and rockers. It may even help the break-in until oil reaches the parts. I would not use DFL on main or rod bearings, lifter bores and the surface of the lifter that mates to the lifter bore.

Here is a Sinn U2 in black, its probably DLC

https://i.pinimg.com/736x/10/91/07/1...198d750833.jpg