Dwight You have a couple of choises. Those 2 lines looks like the rings where not finished properly and caused the grooves. Unless something got sucked into the motor and wedged into the ring land and piston. If the block is stock, Have your machinist home out the cylinders and buy a set of custom pistons. 5- 10 thousands over. This way you can rebuild the block about 4 times before the walls get thin if this is a 427 block. You can do the same with a 428 block. It's cheaper to get custom pistons than buy a new block or sleeve it. I have .015 over size pistons for my spare 428 motor. I don't like running the bores past .030" over. The only way I do this, is to add block filler. JMO Rick L. Ps in the old days the over size numbers where .005", .015", .017" .025" .030" This gives you an idea on fixing the motor Rick. Ps shoot the installer if the rings caused the grooves. He didn't smooth the ends. Poor assembly work.
