the oil filters for all engines are the spin on cartridge type,ac brand,modelpf-25.original filters have a white background with red ac logo and blue stripe lettering.we beleive oil filters were available in 1970 through to 1972 with embossing on the bottom reading..."best way to protect your engine-replace with ac type pf-25"there is strong evidence that un embossed filters were available at this time as well.current ac delco replacements pf 25 is dark blue with a paper tag describing model and instructions.the ncrs pionts system for this catagory works like this,assighn 100% of pionts to a white ac oil filter(with or with out embossing)deduct 70% of points for the current replacement ac filter (pf-25) deduct 91% of points for the current long ac filter (pf-35) deduct 100% of points for any non ac filter.