Mike this is what I started with, 1 line 3.8" diameter. The pump used was from an 82 Corvette.
A 1/4" hole was drilled in the plate for the new pipe. A punch was used to enlarge the hole because it also tapered it like GM did.
Unfortunately I did not take any photos of the finished set up. Another small hole was drilled for the pump wires. The strainer and a rubber fuel line were attached to the pump. The length of the line was adjusted to allow for slight pressure on the stainer against the bottom of the tank. Now to get it all in the small hole in the tank the pump with the hose attached was lowered in, then the sending unit was installed. Both were pulled up and the fuel pump hose was attached to the new pipe. Then the assembly was lowered in and the lock ring installed.
If running fuel injection a reservoir will need to be installed too. I am working on a tank modification for that too but it requires enlarging the opening for the sender. With the larger opening the installation is the same as later model cars and there is enough room to get into the tank to install a reservoir cup.
A few photos of the work so far.
Here are the 2 openings. Both were cut out of the tanks and the larger one installed in the Nova tank.
The Nova tank with the hole enlarged
The larger lock ring assembly installed
the mock up with a junk sender installed.