I recently did this. You can either get an oil pump priming tool, make one from a piece of hex stock, or grab the oil pump drive shaft out of your cam synchro and use that. I used the drive shaft from the cam synchro, which just pulls out the bottom. (I had a spare synchro lying around, which made it even easier.) I didn't even use a power drill for it, just a speed wrench. I don't know exactly how much pressure it generated, but turning it by hand was enough to build up some resistance after several revolutions.