'96 Chevy 5.3L swap

[LS1GMCTruck]

Whats wrong with the existing in-tank fuel pump? It should supply the needed PSI for the 5.3 you need.

[farmtruc]

Whats wrong with the existing in-tank fuel pump? It should supply the needed PSI for the 5.3 you need.

200K+ miles on it and I believe those trucks ran at 43.5psi, correct?

LSx's run at 58psi or so.

It may keep up, but being so old and not originally designed for higher fuel pressure, we're gonna change it just incase.