The tank from "Lela", 1982 720 KC SD for Mercer Island, my first. I did not think to measure the tank:



The "Orting Truck's" 1981 720 Std cab = 13-1/4"H x 32-1/2"L x 14W
The "Bellingham Truck's" 1982 Std cab = 12"H x 41-3/4"L x 14"W




Kicking Nissan FAST for a long time got it to spit up this info. This is (I think) all the fuel tank part Nos. for all the diesel-equipped 720s through the end of the 720 run.
(click on image for larger)

Legend of applicable abbreviations:
Reg = Regular Bed Truck
K/CAB = King Cab
HD/LB = Heavy Duty Long Bed
T = General term for Reg & Long
LONG = Long bed truck
HD/T = General term for HD/LB, HD/W and C&C
Simplified table:

If someone volunteers to type that up or OCR it, I'll include the text version here for the Search feature; I'm too tired tonight to transcribe it.