Yes but read his statement all the way to the end. Todd is correct on his answer .

 

where do I find out what size tank is in my truck. 99 F-250 reg. cab long bed

 

Topping off my 38 gal LB tank will require me to add an extra 3-4 gal OVER the pump automatic shutoff. I don't consider the Harpoon mod a method of INCREASING the tank capicity but a way to allow filling to the cap much quicker due to the foam backing up the fill neck.

Either tank you use (29gal SB or 38gal LB) can be filled up the neck to the tune of a few extra gallons. I can drive close to 300 miles on the first quarter of the tank. After that it drops like a rock.

Do we need to do a MythBusters test on this topic?

 

Long bed = 38 gal
Short bed = 29 gal

+ 4 to 6 gals if you fill to top of the neck.

 

I once put in 31.5 gallons. 99 CC SB