Measuring a Tank
Keys to Remember
- Length is measured weld seam to weld seam
- Fittings are measured from lateral weld seam center of fitting and end cap weld seam to center of fitting
- Indicate which end of the tank is toward the front of the truck and whether it is on the driver or ditch side
- Mark desired finish (milgrade - brushed aluminum or polished - like chrome)
- Use flat measuring tape if possible
- Measure tank from same location as you would when filling the tank (not from sitting inside the cab)
- Refer to the bottom of the page to determine correct NPT fittings
Measuring A Fuel Tank
Finding the Thread Size You Need
To determine the size of pipe fitting thread you need, first use a tape measure or caliper to measure the inside diameter (ID) of the threaded hole were you would like to install the fitting or the outside diameter (OD) of your existing fitting as shown below.
After determining your measurement choose the closest ID or OD dimension listed in the chart below and select your pipe thread size. (Dimensions shown are approximate values and you may need to round up to the closet value).
| Threaded Fitting OD or Hole ID Measurement | 3/8" | 1/2" | 5/8" | 3/4" | 1" | 1 1/2" | 1 3/4" | 2 1/4" |
| Pipe Fitting Thread Size | 1/8" Pipe | 1/4" Pipe | 3/8" Pipe | 1/2" Pipe | 3/4" Pipe | 1 1/4" Pipe | 1 1/2" Pipe | 2" Pipe |
Common Pipe Thread Sizes for Fittings and Plugs
| Pipe Size | Threads per Inch (*NPT) |
| 1/8" | 27 |
| 1/4" | 18 |
| 3/8" | 18 |
| 1/2" | 14 |
| 3/4" | 14 |
| 1" | 11.5 |
