We used to carry both the early model (251-91-051E) and late model (251-919-051K) fuel sending gauges. After testing them out on our vans, we discovered that you can use the late model unit for early model vans! We now sell just the 251-919-051K for all years of Vanagons -- we love the results we get with them, and we think you will too.
For more details on our findings, please refer to our detailed article here.
Note: If you are dropping your fuel tank to re-seal the vapor control system, it is a good time to replace the sending unit. If you don't and it goes bad, you will be dropping the fuel tank again to replace this sending unit. A wise man once said, "There is always time to do it right the second time around." Do it right the first time around! Do it right, cry once!
Application note: This part does not fit 4WD Syncro. You can find that sending unit here.
IMPORTANT: The casting of the plastic "ramps" that lock this sender into place on the tank are not as exact as the OE part. You might need to shave the ramps down a bit (a razor blade works well) to prevent the tank from digging in and gouging the ramps (see photo above). During installation, if you find that the sender stops rotating smoothly into place, stop and remove it. Inspect the ramps and trim away any areas where the plastic is gouged. Additionally, we strongly recommend lubing the O-ring with white lithium grease. You must compress the O-ring tightly to clock the sending unit into the correct position.