How’s it going. I’ve been battling this noise for awhile. I had rebuilt this motor twice now and both times had the same issue. I am leaning towards it being a cracked exhaust manifold or something along those lines due to the fact that the sound was present for both rebuilds and the same manifold was used. The first motor turned out to have 2 flat cam lobes which I found out when the rockers loosened up a lot. This time around everything seems fine I have great oil pressure and all the rockers are not loose. I did the wooden dowel trick up to the valve covers and everything sounds normal. Here is a link to a video of the sound. Any help would be awsome to verify that that it is an exhaust leak!!
