Finding Bore Size

["thenewguy"]

im pretty sure the right cylender was not bored but but the left cylender has a new piston in it and i wanted to know if its bigger or not. if it doesnt say on the piston can i take some vernier(sp?) (the tool that measures in thousanhs of an inch) calipers and measure the top couple of inches to find out? or do i have to take the cylender off the ingine? also i can borrow a tourqe wrench from a guy at work to take it off and put it on. will i need to get a new head gaskett or can i use the same one? and there are numbers all over the head, what do they mean? the tourqe poundage? and is there a certaine order? i dont have the clymers manual so anyhelp would be great. thanks