[FlatheadTed]

Karl has obviously got his sorted ,I am happy with the way mine works my last fill up was to 3/4 it seemed to read ok but will fill it up to see ,After thinking about if (apart from leaks and faulty parts ) you can imagine the fill side of the gauge as a funnel as the liquid lowers the volume decreases or if the funnel was up side down it would increase ,this is more or less what the rod does ,So if you take a 1/8 brass rod and file it to a long taper and pointed it up or down in the gauge this may give the accurate reading and extra volume that Glens looking for ,or maybe you suspend a rod halfway up .A matching gauge and sender from the factory shouldn't need this .I don't know but it may be a way of calibrating ,it . (comments )