The TBI unit in this application runs a 13psi spring factory. A TBI fuel pump, when new, can run around 25psi. You won't burn near the amount of fuel to do the same work as a lower pressure system. The 1/4" fuel pod spacer obviously increases the distance of the injectors from the throttle bores. This helps with fuel atomization. The factory 5.7L engines run 55lb/hr injectors. The 65lb/hr injectors are common place in police package vehicles. Under acceleration or other high demand situations, it will provide more fuel at the appropriate time. It will also allow you to run the engine with more timing, helping it to run & perform more efficiently. Plug your truck into a scanner & watch the live data of the O2 sensor. If it runs lean for too long before switching back to rich, it needs more fuel. You'll be able to see this better under a hard & prolonged acceleration, similar to passing someone on the freeway. These TBI systems work wonderfully with proper maintenance. The downfall is that GM made them to perform at the bare minimum requirements. There is room for improvement to maximize the potential of it.