[GREENSNAKE]

Hey Simon! I had the Same Problem in a 351w Had it apart twice Had that Knock in it Finially found out what it was The mains were good ,Rod bearings were good , Cam was good ,Lifters all adusted right, Finially i Noticed what it was. It Was the Conecting Rod the Piston Skirt sat so far over the rod that you couldnt see it It was bent but really couldnt tell till it was off the piston but sure enough bought a newone put it back together and ran perfect Hope this helps (greensnake)