ly6 swap- having start issue

[xsboost90]

so i have an LY6, mast cam,LS3 intake, DBW,55lb inj, custom harness and tune in place. Started the car a few weeks back with no maf or o2 sensors and it fired right up but wouldnt idle very well, obviously. Got the intake on there with the maf hooked up and installed the o2 sensors. Tried to start the car and it fired right up but started backfiring- which it had a few times before as well. I shut it off and started researching and found it looks like the plugs on the small harness for my PS coil packs was installed backwards after repainting stuff. Swapped that around and tried to start it..nothing. Checked- all eight plugs totally soaked with gas. I pulled them and replaced them with some new a/c delco irridium plugs and tried again= nothing. I did get one good back fire then nothing. Plugs are soaked again. Checked fuses- all good, cant find anything else...tried unplugging the maf to see if something was going on with that- still nothing. Guess i need a scan tool but any ideas?