I recently had my 1957 312 bored .060 over and new cam bearings installed.  When I attempted to install my new Isky E-4 cam it would not even start in the first bearing.  The cam bearing installation appeared okay and Iskyenderian assured me the P/N 301444 cam was the correct one for the 312.  I checked with the supplier where I purchased my overhaul kit and they assured me the bearings were correct and would work in a 292 or 312.  I took the block back to my machine shop and they polished out the bearings so the cam would go in but now the cam feel loose as it goes through the first bearing, yet once installed you have to install the cam gear inorder to turn the cam.  I've heard that some of these parts are made in China and now I wondering if I should get another set of cam bearings and start over.  Anyone had this problem?

buddy