I have a built gen 4 5.3 bored to 5.7 with 799 heads. I did the dod delete and stuck a tick performance tow max stage 2 cam. I came across a weird while attempting to adjust valves I noticed the motor would not turn. Me thinking I dropped something I tore it down the motor spins freely and so does the cam but once the timing chain is installed the engine it's stuck. I do have the black damper and 4x cam sprocket. I'm up in arms about this one

 

Does it spin freely with all the rocker arms removed? Pushrods sitting on the lifters correctly?

 

yes it does! All the pushrods are out. I even hand started the rockers and you can see movement. I just now noticed once I install the cam sprocket alone the cam will not spin. I loosened up the cam bolts the cam spins freely

 

It must be binding on the cam retainer plate somehow. Cam could be machined wrong at the front step. Wouldn’t be the first one…
Are you using the thicker, aftermarket retainer plate?

 

I'm glad you said that! The motor came with a retainer plate with counter sunk holes using torx bit bolts. I assumed it was aftermarket and I took it off and installed a factory retainer plate from a gen 3 motor and it problem solved