Help with checking numbers

The numbers will probably represent the year code, plant code and the last 6 digits, which should match your last 6. You can verify the casting number on the drivers side of the block to make sure it's a 340, and check the casting date on the passenger side of the block to see what year the motor was cast. You can also check the balancer to see if it is a cast crank balancer, which depending on the build date of your car, should have a cast crank. There are a series of numbers stamped under the drivers side head on the front of the motor, indicating that it is a 340 and the VIN should be stamped on the passenger side pad at the bottom of the block, right above the oil pan rail, near the motor mount. Good luck!! Geof