I would send it back and buy elsewhere....all this bending and modifying might bite u in the butt down the line...

Hi guys having the same problem on my end . new sender only reads 1/2 full but when I test the gauge in car reads full?

When this came btt I was hoping that you recalled Mancini & and are going to send it back

Just to close the loop on this and maybe help others who were following this thread. I Returned the sending unit and got a new one which I installed and it WORKS FINE.
As incredible as it seemed, I actually had "2" bad sending units! Thanks for all the help guys--all the troubleshooting steps in this thread might be helpful for someone with similar problems--all good stuff.