trying to confirm any difference between sweptback and squareback concerning the oil passage between upper and lower
i have a swept upper serial ow 283156,
thanks
hey also what else to assemble, nuts orings coupler circlip, what am i missing ?

No difference in the oil passages between OW and the square back. Unless the old lower is from the early 90's or late 80's..

thank you mr. G
needed that before a new lower gets ordered