IT’S HIP TO BE SQUARE
It’s tough to end gap rings in a canted deck engine such as a 409 Chevy. Turn a scrap piece of cylinder sleeve to about .003’ smaller than the bore. Make sure it’s long enough. Use that and it will allow you to push the rings down the bore square. You can also do this with a conventional deck to push the ring past the Torque Plate distortion if you want to get Really nit-picky.