The suction side is big enough unless you have an open oil passage somewhere in the block. Opening the ports leaving the pump are to the filter . You don't want to suck the pan dry. No oil is worse than to little oil.
You can't get the inlet side big enough. There are published tests out there. That is why the Milodon SS pan had a rear sump and the big single pick up in the cover. If you are going to wind it up, you need to use the big tube in the cover and a second pickup that is 3/8 and goes into the original threaded hole in the pump.
You can't suck the pan dry unless you have no oil control. It's practically impossible.