This flywheel bolt kit is good for Ford engines 4.6L & 5.4L. This flywheel bolt kit is by Automotive Racing Products (ARP). Comes with 8 bolts and fastener assembly lubricant with is to clamp load specifications. The socket size is 5/8 12 pt., the UHL or Under Head Length is 1.000", and the thread size is M10 x 1.00. Washers are NOT included! These bolts are built built better then OEM and includes everything you need to bolt in your flywheel. One of the strongest bolts on the market.