Now we’re getting into the area where you can get the block back and start doing some work yourself. Here, the outer edge of the bosses for the oil galleries are rolled back with a grinder to create clearance in a more race-ready double-roll timing chain. If this isn’t done, the edge of the gallery bosses will rub the back of the chain. This is also a good time to chamfer all the other edges on the block (especially around the edges of the deck). Remember, if you do any of this work yourself, you’ll need to thoroughly clean and wash the block to ensure no steel shavings are left behind.