Head replacement
 

I've changed heads on 99' vortec 5.7 fired it up noticed huge vac leak saw my booster line unplugged connect it and it died won't start now with or without vac line it was running around 1600 rpm for about ten mins before I plugged vac line in gauges were good scanner shows nothing from when it was running, I had two cracked heads and drove about five miles home so everything was working before head job it tries to fire but doesn't I've rotated the distributor every way but can't get it to start again

Hold the throttle open just a TAD. Now try and start it. If it starts and you let the throttle go, does it immediately die? If so, your IAC valve is closed all the way. This was because the PCM noticed the idle was very high due to the disconnected vac line and it tried to compensate by closing the IAC(Idle Air Control) valve.

Usually the IAC valve can be reset by turning power on for about 20 seconds and turning back off without cranking. Then power back on and proceed to crank. If this doesn't work, you may have to force it to relearn while driving around 35 MPH. This can take some double footwork to operate the brake and the throttle at the same time.

tried that, put crank back tdc took cap off timing still correct, poured gas directly into throttle body and kept it running a bit, now i did change fuel regulator because i blew a hole in bladder with air chuck now it seems fuel issue but it was running before head job

You do know you have a 25% chance of getting it right when you put the crank at TDC right? Best way in your situation with the 5.7, is to remove the left side(drivers side) valve cover. Rotate the engine by hand until you feel both #1 valve rockers feel loose. Both valves should be closed at this point. This is now TDC for #1. Now you can readjust your dizzy cap to point at #1 wire.

The above also works the same for the little brother 4.3.

thank you for your suggestions my timing is correct, pressure test my fuel pump apparently it decided to quit on me while I connected that vacuum line changed it out now adjusting valves in the morning

Well that was weird.