they are a bolt on- will need longer lug studs - some say there is a spacer needed
http://www.brphotrods.com/mm5/mercha...ory_Code=BRK14 only thing you have to do is adapt the brake lines and the e-brake cable. I also sell a caliper bracket to mount ls1 front brakes on a 68-74
http://i156.photobucket.com/albums/t...9/ls1brkt2.jpg
Rich