Here's a pic from Summit.

http://www.summitracing.com/parts/TAY-2522/?image=large

The ones in question are the ones on the LEFT. They are silicon coated.

Question I have is can they touch the header? I've used the ones on the right before, but could not get any locally, but I can get the ones on the left.

I don't want them to melt all over my tti headers

codfish

Sure, they can touch the header and they will survive, and will not melt.

In that scenario, the plug boot on the wire STILL MELTS, only it melts inside the sleeve where you can't see it.

I've seen it happen about a half dozen times now

Do what ever you can to keep the plug boot from touching the header

My kid has the ones on the right on a few of his Taylor wire.They have been on for 3 years and he has 2 1/8 tubes.No problems with the ends ever.His gets street driven and raced so it gets a ton of miles.My 440 just has Taylor wires and they are 9 years old at least with 2 inch TTIs street and strip.No problems.Rocky

Haven't used the ones on the left. Have the woven ones on the right on a 454, cast iron manifolds, been on there for years and as much heat as the manifolds radiate, zero problems; but they don't touch the manifolds. A buddy of mine has the woven style on his 454 and they have burn spots where his touch his headers.
Not really the answer you're looking for, just passing on my experience.