Don't get it right, just get it running. 85 318 roller

Asking on line will just have other people spending your money. I'd take measurements to figure out if there is enough taper that you need an overbore. Thing is if its too much taper and wear it will burn oil(grey smoke out exhaust) once I determined i can get away with a re-ring yes Id run the stock pistons. To not check the ring gap is a gamble IMO. You can clean everything spotless but if parts are worn you'll have problems. I'm speaking of a general "Overhaul" the thing is most get too into re-machining and blueprinting which gets expensive. Now generally you'll find you have to redo the heads but still sometimes you get lucky guides are tight and all you need is to install seals and lap. More times than not though the heads get redone which is pricey itself lately. For me a general overhaul is clean and check always a new cam and lifters, bearings, seals etc. and timing set and oil pump. I replace those parts without question.