No crank

[Blake1999]

Hi I have a 5.3l out of a 2001 Tahoe swapped into a 1985 c10. I have a painless engine harness all wired in and the pcm is completely stock. I have talked to a few people and I have heard the engine should crank but not run. Well when I turn the key the fuel pump cycles as it should and then nothing. I'm getting it tuned soon but I'm trying to figure out why it won't turn over before I take it somewhere to get tuned and then it won't run. So my plan is to check the starter and then grounds. Is there anything else that could cause this problem? Also how many and where should my grounds be for this swap I know Ls are ground sensitive so I just wanted to make sure it is grounded properly to avoid future problems anyone have any advice or auggesrions? Thanks!!