It's hard to say with out hearing it. Are you sure your valvetrain is adjusted right? Did you check piston to valve clearance? If you checked all the normal stuff and you still think it is the rotating assembly you can pull all the plugs and rockers then turn it over by hand. If you feel any little thumps or it gets stuck somthing is not right.
When I assembled my 347 the rod bolts would hit the girdle when I did the final check before putting on the oil pan. The girdle was for a 347 and allready had notches ground in it but it still was not enough.
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NA 347 W/ stage 2 Canfield heads, out of the box Victor 5.0 intake, solid roller cam, Aeromotive fuel system.
MY CAR
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