i have a similar crosshatch head ,has the BRA code and 097832 .can't see from my pics the 10 .date code is .-1-85 it was fully ported big valve head from vulcan engineering, so not sure if that was an rs1600i head originally or not.supposed to be the best heads as you can go larger on valves.not sure how true that is but from a rough measurement it looks like 43mm/38mm valves.