The Engine isn’t Running... Yet

Bright and early on Sunday morning my Dad and I got right to work on finishing setting up the engine. I had done the research I needed to hook up just about everything else that needed to be. My dad worked on hooking up the ground wires that the previous owner had disconnected for some reason while I routed the hoses, vacuum lines, and miscellaneous wires. After about two hours it was finally time to try and start her up, the big moment.
My Dad hopped in the cab and right as he started cranking the engine gas started pouring out the injector rail... Whoops! That was an easy fix, the fuel filter on the newer engine didn't fit the bolt we used from the 80s engine so it was leaking; After swapping the bolts we tried again.
The engine wanted to start but it just wasn't running. It'd pop off and almost start but it wasn't continuing to run. We couldn't smell gas and the plugs were getting spark (My Dad tested them and got woken up hahah) so our best guess for now is something's up not right with the injector rail. Either the pressure in the fuel system isn't right meaning we hooked up a line in the wrong spot, or a fuse went somewhere, or maybe even I plugged in a wrong connection somewhere, we just aren't sure yet. After wokring on the truck for another 4 hours, a total of 10 all weekend we were ready to call it quits for the day and go home and search forums and manuals to try and diagnose our issue.

Sometime this week we're gonna go back up to my Uncle's shop and troubleshoot the engine, but for now I'm still looking into different possibilities of what could be wrong and how to test them.