Help settle an arguement, oil pump shaft

Dad has been helping me rebuild the 273. He says you can't install the oil pump shaft with the intake on, I say you can just may have to devise some kind of tool to get it lined up right. I am still probably at least a couple months away from engine install and startup, and therefore I wouldn't waant to prime and presurize the oil system now(using a homemade primer), would I? And I would like to get the engine sealed up.
thanks
Aaron