Oil capacity is about 4 litres, as for recommendations, if you only have Halfrauds to choose from (ie. not buying off Oilman on here) then I'd use Mobil 1 Motorsport. Some people would say not the best but it'll do. Don't forget your fuel filters, it's an old petrol tank after all. Might as well throw in some Ford Motorcraft 701 plugs as they're only £12 a set from Ford.