.040 over Hyperutectic 428 Pontiac pistons. I purchased these several years ago for a 428 build. I thought it would clean up at .040 but it wouldn't and ended up needing to bore the engine .060. They have been setting on a shelf in my shop ever since. They are new and never installed or even removed from the packaging except to take the pictures. These pistons will give approximately 9.4 to 1 compression with a 72cc head for pump friendly operation. Free shipping to the 48 contiguous states only.