You should replace the camshaft bearings every time the block goes to the machine shop. These bearings fit all 1275cc blocks without tappet covers on the back. It's almost too simple and thus often overlooked during a rebuild. Camshaft bearings are pressed into the block and thus are usually done by a machine shop. You would not rebuild an engine without replacing the rod bearings, so why not the cam bearings? Two sizes of cam bearings; blocks with tappet covers use VPC956, those without tappet covers (eg Austin America) use VPC989.