The 29D engines were fitted to the Austin-Healey 3000 MkI. 1959 - 1961. The "RV" is probably "RU". According to the two factory parts lists I have, "R" indicates an overdrive was fitted and "U" indicates a center shift gearbox. I don't believe the parts list because the center shift gearbox wasn't fitted until later, during MkII tri-carb production. I wonder if the parts list "center shift" refers to center of the car, rather than a steering column shift.