No start help after swap; 2008 5.3

[Jonboy]

Checking to see if some of the gurus here may have any help for me. I swapped a 2008 5.3 (non flex fuel) into a '77 C10. Used an aftermarket stand alone harness with a "tuned" PCM. I am having a no start issue. Fuel is 55 at the rail during prime, moves from 55 to 65 during cranking (assuming that means the injectors are firing?). New Delco plugs; have a bit of a burn spot on them, but not complete. Compression on all cylinders, anywhere from 160 to 170. I pulled the injectors and let them soak in a container of Seafoam thinking they might have been clogged. I am getting spark on #1, and there is signal at the injector plug verified by a noid light. I do have power on the switched power wire during key on and crank, constant power is good.

What could I be missing? It doesn't even act like it wants to try and start.