Block off...?
On the 787, all you need to do is remove the 2 allen head bolts that hold the pump on. Then, remove the teflon shaft. This is the drive gear.
Once you do, put the pump back on. From there, you can pinch the inlet line from the oil tank to stop the flow of oil to the pump. If you do more than that, then you'll have more work to put the system back together if you want.
I think after you blow about $75 dollars in one season of premixing, you'll probably want to put the oil injection system back together.
Remember, you still have to leave the oil tank, along with the rotary supply and return lines in place. You don't need to have but about 1/2 a tank of oil in it but you do need to leave it installed............:cheers: