Free Next Day shipping. Time-Sert J-42385-2000 NorthStar M11x1.5mm head bolt thread repair kit. Note this kit is for 4.0/4.6 Northstar engine blocks that have two depths for head bolt holes. Depths are 32mm upper bank and 51mm lower bank. The depths refer to the depth which the 30mm inserts are placed. This kit includes ten of the 11155 30mm inserts - 20 are needed for the entire block. See below in "related" for the link to more inserts.