fuel guage reads full with the ignition off 63 ch tk

[jonzcustomshop]

I've been trying to get the fuel gauge to work in my 63 chevy truck.
I tested everything, and found that the sending unit was not working.
I pulled the sender out of the tank. the metal strap that goes from the sending unit to the connection was broken at the top of the connection. I soldered this connection back together.

the guage now works, but does 2 things that are not normal.

1)the gauge needle moves to past full when the ignition is off. when you turn the ignition on it moves back to the level of gas I have in the tank (1/8). I filled the tank a little and the reading increased, so it seems like the sender is working.

2)while driving the needle cycles from the fuel level to empty and back, sometimes it goes smooth, sometimes it jumps, and sometimes it just stays put at the 1/8 mark.

I also have what seems to be a good sender out of a 66 chevy truck (on a bench test it moved the guage), but I had heard that the ohms changed from 0-30, to 0-90 at gm in 65... I don't know if this is true for this truck, lmc truck just lists one part # for a sender for a 60-66 chevy/gmc truck.

any help or pointer would be appreciated!

*** a guy on the hamb mentioned that the sender might be worn, and that is why I am getting a sporadic reading, I am going to try the sender out of the 66, but I am still unsure why the guage moves to full with the ignition off...