This is a rebuild of the Circle Track dyno mule that we’re upgrading for future testing. Both the rod and main bearings are supplied by King Engine Bearings. We chose its XP performance bearing line because they’re designed to withstand high-load endurance applications—in other words, stock car racing. The first step is to make sure that both the housing bores and both sides of the bearings are clean and grit-free. Fit the bearings into the block so that the tangs on the backsides of the bearings fit into the slots in the block. The grooved bearing shells fit into the housing bore half in the block, while the smooth shells fit into the caps.