ok so i have been looking to upgrade from the original dog of a 305 for my moredoor. i have found a 72 model 350 4 bolt main out of a truck for the low low. the only thing that i am apprehensive about are the score marks on the cylinder walls. they arent able to be felt by touch but stand out like a sore thumb to the eye. is this something that i need to worry about? i want to rebuild my new engine myself without sending anything to the machine shop. is this advisable?