Miles to a tank (1.7d)

[kc_08]

Hi I've not long got a corsa b diesel for a work horse (1.7d) and the fuel gauge doesn't work (he put petrol ones in :/) so rev counters abit happy and no gauge I changed the clocks and still no gauge haha, so before I get a chance to take the pump out ect and check everything, just wondered roughly what people get to a tank/gallon ect as Parker's says 550miles but pfft I take them with a pinch of salt.

Also another million pound question what's needed to change to a 1.7td izuzu engine, she's a 1.7d izuzu on a p reg at the moment, I've asked a few people and had a quick look but someone with all the right knowledge to let me know what I need ect as was gonna take the whole lot out of another car.

thanks for any help much appreciated!