P1345 code after replacing timing chain and gears

Question

I have a 2001 Silverado with the 4.3
I replaced the timing chain and gears. I lined up all the marks on crank and cam gears as well as distributer and cam balance gear. After putting it all back together i tried cranking it. I then changed distributer cap and rotor button. It threw the p1345 code and would not crank or run without me holding the gas pedal down. I checked the number 1 plug with the rotor button and it was off so i lined #1 plug TDC and pulled distributer and turned it to the 6 mark. Replaced cap and tried cranking again. It backfired through the intake and now will not start. I checked the #1 plug with the rotor button again and now it is off and will not line back up. Did it jump time again? Please help!!!!