I have a '74 Duster with a mild 440. I am getting about 10mpg and am wondering since my gas gauge doesn't work... how big are the factory gas tanks? I am thinking it is 16 gallons but... I am not sure.

I have been using my GPS to keep track of my speed (speedometer doesn't work) and my mileage. If I knew how big of gas tank I have, I could figure out how far I can go between fill ups.

Does any one know?

I own a 1971 Duster that I've had to fill more than once after draining it for the winter, the factory service manuals say it holds 14 gallons I've put 14.5 in mine but it has a round sump welded on the bottom and I filled it all the way up into the neck so I could see the fuel level The 1967 to 1970 A bodys held 18 gallons according to the FSM, they won't fit into may car, I treid Google 1974 Plymouth gas tank sizes That or drain it dry and then fill run it until it runs out of fuel and then fiill it up into the neck Put a five gallon gas can in the trunk with five measured gallons in it before driving it dry

The 74 dealer data book says 16 gal, same as you were thinking.

http://www.hamtramck-historical.com/imag...Duster_0023.jpg

Very Good to know! Thank you!

68-70 Abodies had an 18 gallon tank (US Gallon). I have put one of those tanks in the 76 Duster that I had . . . used the 76 sending unit and everything worked fine. The extra two gallons sure makes a difference on the road !!!

Mark