Milodon aftermarket main bearing caps not only strengthen factory 2-bolt blocks, but they will also add a measurable degree of strength to 4-bolt blocks. They are made from precision-machined, high-strength steel, which has the proper balance of strength and flexibility to allow for the transfer of increased shock loads to the crank and bearings. The secret is in the side bolts. They are angled so that they pull from the side walls of the block and not from the flimsy main web area. They'll also load the cap against the register step, which will prevent dreaded "cap walk." They can be installed by anyone with a hand drill and a tap and they come with the necessary bolts, washers, and drill bushing to complete the installation. Milodon main cap kits are available in your choice of angled or straight bolts.