Depends on the donor for that. And yeah, a TBI 2.5 from the 80s is around 14-15psi and a 4.0 is going to want high 30s through high 40s or so depending on year (I always forget which is which) so you'll need to switch that.
carbed sender/pump units are 2 wire (no fuel pump feed, just ground+signal), TBI and MPFI ones are 3 wire. 91-92 senders have a resistance curve that runs opposite 90-down ones, so your gauge will go backwards, and it's not solvable by simply switching wires or anything. Some people have swapped just the fuel gauge in the cluster with a little custom wiring and gotten it working.