Hi, Josh; I tried responding yesterday, but for some reason it wouldn't go thru. Sorry.
A couple things come to mind which are common for this year/make/engine. First, you need to check to see if you are getting spark while cranking the engine. If not, could be a faulty ignition control module or a faulty crankshaft sensor (CKS). If the engine will restart after sitting for a while, I'd suspect the control module. You can verify it to be a CKS with a scanner, watching for RPM while cranking.
Although the fuel pump has been replaced recently, be sure that you have fuel pressure with the ignition turned on. If this is a Vortec, they require 55psi just to start.
Good luck.
Loren