Dura-bond “Red Box” Bi metal Seamless +.010″ outside diameter/over size polymer coated cam bearings. Applications GM Small Block Chevy Gen 1 , flat tappet, soild roller cams unlimited spring pressure. Engines 283/302/305/307/327/350/383/400cid 1964-2003. For blocks with repaired cam tunnels to correct machining defects. Has standard journal I.D. ( Note these will not fit standard cam tunnel blocks, bearings O.D. measure 2.030″ ) Made in the USA. Please e-mail with questions.