Very, very interesting to be sure! Perhaps we're onto something here...
Mine is a 76. It takes the 4.8 US quarts recommended by the book.
davey:It takes the 4.8 US quarts recommended by the book.
My book recomended that amount too (that works out near enough 4.5 litres, as I make it). I've just re-checked what I put in, and it was 4.25 litres, so almost the full amount. And it is reading way above the maximum mark on the dip stick. Nearer the 78mm mark on the dimensioned photo I put up on the last page.
Mine's a 1977.