I use Valvoline VR1 too . Its a race car grade oil that should be changed at 3000 miles but that`s annual mileage for most classics . I always get correct spec filters for my 1980 C3 on ebay . The last two have come from Malibu Parts in Lechlade , Gloucestershire and delivery is prompt . Or try US Automotive in Bedford or Frost`s Wellingborough . Both stock vast amounts of American car parts.