STEP 04

With about one thousandth of an inch to come out of the tunnel to get us spot-on for factory bearing clearances, Trevor gives the block a line-hone. This takes a tiny amount of material off each edge of the main tunnel, and our aim is to get them all exactly the same. While it would be fine for an ordinary engine to have small imperfections with slightly varied bearing clearances, we want to get this thing as perfect as we can. Factory-spec bearings also have a bottom and a top tolerance, which we’re right in the middle of – perfect!