I own a 1988 Hess & Eisenhart XJS. When I purchased the car a forum member posted that my car belonged to the junkyard, but my car is complete and running.
The pump you need for the lower tank (inside the car) is CARTER P74096. This is a low pressure lift pump to push fuel from the lower tank to the upper tank.
As far as the fuel sender assemblies go, the dials on both have to be clocked at 2 o'clock in order to synchronize them.

pic of my Hess car when I bought it 2 years ago