gas tank plastic/metal
 

I need to replace my fuel tank.
So it would seem a no brainer to get plastic and forget about it. But it doesn't appear a no brainer on what works with what.
The sending unit should be the same for both tanks it appears, but jeff shows a unit for year specifics.
But they do all show the same diameter.
What changed after 84 where jeff is showing tanks/sending units that fit 80-84, 85-86 and 85-97 and the rock doesn't.
When did Ford put electric fuel pumps in gas tanks? I thought my system was mechanical only but seeing these sending units.
It appears I do have pumps in the tanks along with the mechanical. Was this for 460 only?
Did you replace everything when you did the job or just the tank? I replaced everything in my 79 but that was a little more economical.
Which electric fuel pump did you install? I ask because you can buy a spectra tank kit that comes with everything.
Or piece it together ?
Does it really matter if it's a steel tank vs plastic tank with these pumps/sending units?

80-84 the ohms are the same in '85 the ohms on the sending unit changed.
80-83 was all the same sending units but '84 they switched to the big sending unit for in tank electric fuel pump.

I know this for sure because we put a '84-86 saddle tank in a '82 F150 and put a '84 sending unit in to make the factory '82 fuel gauge to read proper. With the '85 sender the gauge would read full when empty.

That makes sense appreciate the insight on the different sending units.
Does anyone know if the fuel pump matters for plastic vs metal tanks as I see in the description for some
"Fits Front; With 19 Gallon Tank
Or Rear; With Plastic Tank"

Doesn't seem like it really should matter, should it?

I can't explain what happened to you when you were tank swapping, but all the sending units worked electrically the same up to 86. Then in 1987 they changed the instrument cluster, and that is when the sending units changed also and worked electrically backwards from the earlier units.

The early tanks had the smaller hole in the tank, there were no trucks with electric fuel pumps. Around 84 or so they did start putting electric fuel pumps in some of the 460 equipped trucks, I have heard but not seen that some of the f250/350 351w equipped trucks may have had the electric system also. When Ford came out with this system, they changed all their tanks to the large hole, even if the truck did not have electric fuel pumps. They kept the large hole tanks on all trucks up through 1986.

I don't know. I was going off what the boss said few years back he said '85 was the first year for the large hole tank for in tank pump so I called in a 85 19 gallon saddle tank and a 85 sending unit. Read full when the tank was empty. Pulled the sender out and replaced it with an 84 sender and plugged it in and it read Empty when empty. No wiring changed or anything. I read online that the first year for the large hole tank with the in tank pump had the same gauge resistance as the earlier small hole tanks. Then in '85 like the one we ordered it went to the reversed resistance.

Its quite possible I got the years wrong maybe its 85 is the same and we ordered 86 parts I cant fully remember but I want to say it was a 85 that we ordered parts cause boss is quite adamant about always picking a year that ends in 0 or 5 for some reason.

~Update~

Ok I double checked just to make sure, 84 still had the small hole. 85 was the first year for the big hole sender.

https://www.rockauto.com/en/catalog/...fuel+tank,6268

So we ordered a tank and sender for a '86 and the '86 sender did not work on a '82 gauge it was reversed so I ended up calling in for an '85 sender and it worked fine. So if they worked the same up to '86 then I don't know what it is but the '86 sender we got didn't work it read full when the tank was empty and the previous year sender read empty on an empty tank.

I also looked at the specs on rockauto for the senders as well. Looks to be the same up to 87 then in 87 there is no listing for specs. Now I wonder if the idiots at the parts house shipped us a '87 sender when we ordered for an '86. I know the paperwork said '86 as the year.