Headgaskets Aluminum Heads

jos51700 said
I like the Cometic/MLS because as the head expands at a different rate than the block, the leaves of the MLS are free to expand at different rates against one another so they minimize stress in the gasket itself. A composite gasket might just tear apart internally.

Full disclosure, I've not used any of the other gaskets in this thread. I've done a dozen Neon heads and a billion all-aluminum motors (motorcycle).

Not only do the heads expand, every time there is a firing cycle the head lifts away from the block. Those embossed trenches in the MLS gaskets basically function as pneumatic springs that follow the head as it lifts from the block and keeps the combustion sealed.