Does anyone know what the length of the stock pushrods in the 215 V8

should be? Installed new lifters,pushrods, and reconditioned rocker

assemblies in my 63 olds 215, and now the engine clatters loudly at start

up and gets worse as it warms up. Cam lobes looked good to me showing

no signs of wear. New pushrods are approx. 8.25 long. What have I done

to the engine if these are not the correct length?