Why would you want to fill that block? I know a lot of racers that have used filled and then unfilled blocks after they found a good block that sonic tested okay. Why would you want to have two different temperatures zones in your cylinders? Especially on a car that will see a lot of road time If your block is thin buy a better block, no bandaids One thing to keep in mind on block fillers is all cement shrinks as it cures, even expensive commercial non shrinking cement BTW, I do have three brand new bottles of Moroso block filler if you want to buy some of them at a good price