340 coolant in oil

I should ask if if it is a 4.07 bore in the block? (4.04 +.030 340) It would measure just a hair over 4-1/16. I ask because of what looks like 2318 piston number... i hope I’m not bombarding you with too much at once here, I didn’t get the weather I hoped to have here so I am unable to work on my own junk today...