help with priming

I'm getting so close to firing up my 408. I had it built by a local guy. Today we were priming the oil pump and almost immediately I had oil in the passenger side, but I can't get anything on the drivers side. I was building lots of pressure, and spun the shaft for a good 2-3 min a few times. had a guy turn the motor over a few times too. Anything I should check before ripping into the rocker assmbly and removing the intake and head? Please help! This is my first build, so it's all been a learning experience.