Having once worked on my TR8 oil pump and used the vasoline packing method for re-priming, I wished for a better way. Then, reading of said better way, I tried it, too. This consists of overfilling the sump by 2 quarts, raising the rear of the car a bit, and operating the oil pump gear by means of a slotted shaft inserted after removing the distributor.
Now, that's a royal pain, too, if like me you have a replacement dizzy with a very hard-to-reach holddown bolt.
So I did this, after I opened the oil pressure valve, spilling the prime again: I removed the oil warning sending unit and fitted a small piece of copper tubing with appropriate brass fittings into the hole [it's pipe thread], leaving the tubing pointed up.
This hole is right on the side of the oil pump. I then attached a piece of rubber tubing and a small funnel. Then I poured about 50cc of motor oil into the funnel, until the flow slowed down. I think this filled the cavity around the oil pump gears. To be safe, I also poured the two extra quarts of motor oil into the sump via the regular filler opening.
I started up the motor, and in 4 long seconds, bingo, oil pressure. [I have a gauge in my car instead of a sending unit, but the method is the same]. BTW, remove the two extra quarts afterwards.
This is so easy, I can't believe it hasn't graced this forum before [that I can find].
Afraid of running your motor for a few seconds without oil pressure? You do it all the time, whenever you change the filter!