Engine tick/knock

I'll try to keep a long story short. I own a 2003 Tahoe 5.3 Flex Fuel 166K miles. Was swapping my motor and tranny into an 04 Yukon just for the body and had run into some obstacles along the way. Had to sort of Frankenstein this beast so for clarification My 5.3 Motor and its OE Tranny are being used as well as my exhaust. I had to use the 04 Yukons fuel lines therefore using its intake with its injectors therefore using its harness and computer. Once put back together we finally got it to run but now the motor is making a ticking noise which was not present prior to the swap. I did have a misfire code a while ago but atter a tune up that went away. Did a number of things to try and fix it which ended up being Cylinder 7 & 8 lifters (those were the ones misfiring previously), Pushrods, Rocker arms, as well as a number of gaskets and seals that would need to be changed while the motor was taken apart. Noticed number 4 coil was loose and the ticking was prominent there but once disconnected still pretty prominent. For context I work at a GM dealer and have one of the techs doing the work but l've been present throughout the job and nothing seemed out of the ordinary with the process but none of the techs can give me an answer as to what could cause this. As stated never had a problem other than the check engine light before the swap and now the motor is acting up. If anyone can give any insight on this it would be much appreciated as I'm running out of options and no longer have a truck I can use for the time being. For some reason I can’t upload the video I have so hopefully with the provided information i can get some feedback.