You should be able to find a larger fuel tank at almost any truck wrecking yard. The only thing you need to consider is how wide it is in order to fit it between the fender skirt and frame rail.
Looks like mine is about 100. That's some great range. I have WMO system about the same size I think I may add as well. I wasn't going to run a second fuel system but the first 4/8 tanks of black oil fuel will pay for itself. I'm only planning on driving about 500 miles a month. So if I only have to go find WMO every couple months to double my MPG?! Plus i think it makes the entire engine last longer being lubed with the mixture.
I'm not sure if i want the hassle? All the tanks on a bus with adding two or three more fuel tanks. Ive always done it for the challenge. Its so easy but it smells and like WVO it can be messy.
If you get 8 or 10 mpg and have 100 gallon tank and drive 500 miles a month I'm not sure that is enough miles a month to justify the conversion. You have to remember to switch over to clean diesel when you drop off the free way.
Its the prefect situation for a system since your not chasing oil but every 3 months and only 50 gallons. But your only saving $50.00 dollars a month i think?
Last time I was driving to the east coast and back and fuel was $4.50 a gallon
There is no standard size tank. It could be anywhere from less than 30 gallons usable to over 200 gallons usable. It all depends upon what the original purchaser ordered from the factory.
Somewhere on the tank there should be a tag that tells what size it is. It probably is not in a convenient place to read it though.
You can take outside measurements and do the math to determine the cubic volume and change the cubic inches into gallons.
The VERY BEST way to find out how big your tank is is to take the VIN to the dealer and ask them how big the tank is. There is NO tag on the tank saying how big the tank is.