Rear Main Seal Cap Bolts. These are the very specialized countersunk bolts that hold the Aluminum Rear main seal cap to the block. These are BRAND NEW, and feature some design improvements over the original factory bolts, such as a thicker underhead washer surface. Finished in black oxide for good looks and corrosion resistance. The 3/8" 12 point wrench surface on the originals can become rounded off, and removal then requires basically destroying the rear main seal cap, so go with these brand new ones for extra insurance. Sold in sets of 2. Use one set per engine.