Stage 8 Locking Header Bolt Kit with 1 inch Bolts features a locking header bolt kit with 1 inch bolts for Ford big blocks 390 - 460 cu/inches including 351C and 351M and GM Big Blocks 396 - 502 cu/inches. It includes (16 ea) 3/8-16 X 1 inch 6 point bolts with DHH (includes 3/16 inch recessed allen Head) and matching locking hardware.