LA-CO EZ Break Nickel Grade Antiseize Paste, 2600 Degree F Temperature, 8 oz Jar with Brush in Cap

Its hard to do a qualitative test on something like this, but it seems to be about as good as the best high temp paste that Ive used before. Nickel is supposed to be the best.

Used it to install new spark plug into an aluminum block. So far, so good, as expected. LA-CO nickel grade antiseize paste has the reputation as being the best out there.

I use this on anything that screws into aluminum.

The stuff works well you never have to worry about the bolts rusting together