Fueling & Injection - lt1 vs ls1 sendiing units

Hello all,

I don't know how different they are. I replaced all the wiring harnesses in the car from an lt1 to ls1 but it won't plug into the lt1 sending unit now.
I am going to run dual walbros and a hot wire kit so will this matter? Should I try and find a 98 unit and use it if it works with the metal lt1 tank?

Thanks for the help