2006 GMC 2500 HD 6.0 LQ4 last engine spun crank bearings. Swapped in a ATK HP109 https://www.jegs.com/i/ATK-Engines/059/HP109/10002/-1 I believe this is the cam they put in them. https://www.howardscams.com/hydrauli...cams-196765-12 I'm very new to HP tuners so sorry if some of the changes I made don't make sense I am just using whatever sources I can get on google and youtube, so made some modifications to the tune and got it to start and idle. After about a week bolted up the exhaust to the headers and since then have not gotten it to start. I checked for spark on all cylinders which it has. fuel pressure is 58 psi, removed fuel injectors and made sure they are spraying good. set engine to top dead center cylinder one and made a mark on the timing cover and crank pulley and verified with timing light spark is happening wherever I set it to in cranking timing. compression on all cylinders is around 160 psi. using camera and manually turning engine over made sure all valves are opening and closing. I cannot figure out what I am missing, I feel like its something with the tune I am missing. either that or I overlooked one of my basic checks. No trouble codes setting either. Any help is appreciated. I will be uploading stock tune with the last tune it ran on when I was dialing in the idle. along with a log of when it ran and a log of no start. Mind you the no start log has a low battery voltage while cranking since then I have replaced battery and starter with same result. Let me know if I need more PIDs on the log and which ones I need.