If you have a fuel tank designed for carburettors then you will need to add a swirl pot as shown below as the high pressure fuel pump must never run dry;

Electronic fuel injection requires high pressure fuel be supplied to the injectors. If you have a fuel tank designed for fuel injection then you will have a system similar to the below;

In some cases, clearance issues with bulkheads means you cannot fit the return fuel line on the fuel rail. To combat this a “single end” system can be used;