Uhhh, do you have the correct gaskets? If so, there's not much that can go wrong. FWIW, I have found that prefilling the oil filter actually takes longer for oil pressure to come up, but only by a second or two. If you have the correct gaskets, pull the plugs and crank it in 5 second bursts to keep from overheating the starter motor. If pressure doesn't come up then, in the words of the Chinese aviator.. Sum Ting Wong.. you have a problem.