Popping at idle and Big loss of power
 

Whats happening when your engine makes popping sounds at idle. I just put my engine in and its is popping really loud at idle and it runs like crap.

misfires, stuck valve, exhaust leaks, etc.

What about not setting up the roller rockers properly.
I'm going to pull all the plugs because I cranked the motor over for 2 days and it would not start. Maybe they could have fouled when the opti was installed wrong. Check the wires to make sure they are not arking off anything.
Other then that I think maybe the timing set was not installed properly. My buddy keeps telling I must be on exhaust stroke not compression.
If I lined up both timing makes pointing at each other that should be correct.

Sure... if an exhaust valve isn't closing - whether its stuck, or adjusted too tight - you're going to hear it pop.

Are you sure you have the plug wires connected in the correct firing order?