Help! I've been gathering parts to restore my 1967 O4C big block car for years now. My radiator was damaged and discarded due to an accident back in the '70's. I need the "OL" coded tank for the right side. Do I need a tank that is coded with a "D" (for April),or can I use one with a B,or C to still be historically correct? What has been seen on other original radiator cars? Thanks,anybody,Andy