I need to shield some SS lines off the MC. Wrap them tight or create a sleeve and allow an air space?

How far away is your heat source and what is
the source

I'm leaning towards air space, with a very thin reflective shield type material, SS is pretty good at resisting heat transfer if you go with a metal.

Header. Varies from 3/4" to 1 1/2".

I used a header rap, tight to control the temp
on my trans lines(they are about a 1/4" away
from my headers).. I rapped both the headers
and the trans lines

We made an aluminum shield (on a Duster) never had a problem with heat again. Either way I would leave air space (tube type). Contact means heat transfer to me.

Thought that air would act as an insulator. Thermal coated headers and the wrap kills the coating, so i'm stuck with shielding each individual brake line. Fenderwell headers bring the pipes close to the brake lines and MC. Have a shield for the MC.

Fire sleeve works great for that.

you can wrap it tight with header wrap, soak it with high temp paint to keep it from unraveling and use stainless safety wire to secure the ends. Works real good for insulating the headers but they don't last as long before cracking. Stainless will only go so long before cracking compared to a real good metal like Inconel...Tim