Hard Blok water Jacket filler is a specially formulated, cement-based product with refined, size-graded iron particles combined at an optimum ratio to provide maximum strength, vibration dampening, and heat dissipation required in high performance race engines. Its coefficient of thermal expansion is identical to cast iron engine blocks. Product has been tested and proven effective in aluminum blocks.  Racecar Engineering™ is proud to distribute and support the entire Hard Blok® product line.  Shop here online now for the most popular items from Hard Blok®.  Always remember, if you don't find what you need on here our website, we'll gladly special order the item for you directly from the factory.  Please contact our Technical Sales staff for complete information.