I've just completed rebuilding my Suburban's 350 into a 383, and feels/sounds so, so close, and I'm not 100% sure what I'm missing yet. I think it might be just not getting fuel, but then I did some reading about people having the distributor put in 180 degrees off of the cam (or the crank, I'm not sure), which causes backfiring out of the intake, which seems like what might have happened when we tried to use our starting fluid.
I've actually got a video of us trying to turn it over here in this link.
Does this sound like just not getting fuel? Or does it sound like I might have that 180 problem, or both?