I have a 1970 Olds Cutlass Supreme convertible, 350 2bbl.

When I filled the tank a while back, the gauge moved all the way to the “F”. As I drove it a few times to shows, etc., it moved down to between ½ and ¾. As I continued to drive it, the gauge didn’t move any lower, which I foolishly was not paying attention until it (of course) ran out of gas while returning from a show. I filled the tank and the gauge dutifully moved back to “F”, which I will closely monitor along with the mileage.
My suspicion is a faulty sending unit, it is of course 51 years old, rather than the gauge.

Should I just go ahead and order a new unit and have it installed?

The fuel pump has 2 lines so the sending unit needs a return line (2 connector)
Fusick has one listed part # FTU680-2 for $95.00 which seems a bit steep to me, so I found one at OPGI for $42.99, but not in stock (!)

Carparts.com lists one for $29.99 sale price (list price $55.43)

 

It's probably the sending unit... probably.

 

Have you looked at RockAuto?

https://www.rockauto.com/en/catalog/...ding+unit,4436

 

Thanks

Yes

 

Amazon shows two in stock @ $38.33

 

Did you check the terminal for the ground wire leading from the sender? If it is not making a good connection do to corrosion, the fuel level gage can travel back and forth from full to the correct reading.

 

The sending unit may be getting stuck at the 3/4 position. Drive the car until you know the fuel level is below 3/4, the bang on the bottom of the tank with you fist to see if it dis-lodges the unit.