So I am extremely close to getting my Stag running, the only thing in the way is that the engine will not build up oil pressure. When I removed the oil filter it was as dry as a bone. Then my mechanic and I thought that the RTV that I have put around the oil pump was blocking it. After removing it we found that it was fine, the O ring had blocked the RTV, and the pump seemed to be fine and in working order. So what am I to do now. The engine is the original Stag V8. Also as added insult the oil drain plug that I put on now refuses to come off so I can change the oil 
. (changing to 20w-50 which my Mechanic always uses when starting rebuild engines. I had synthetic in there which he says will not seat the rings) Any advice would be a great help - Ryan
This is going to sound like a foolish question, but are you sure the oil pump is turning? I've never actually been in a Stag engine, but the pics I find of the oil pump show it being driven by a hex shaft which I assume runs off the bottom of the distributor. So if the dizzy's not in, it can't spin the pump. Or, if the shaft is not the right size same problem. I once saw a distributor gear roll pin that sheared, the dizzy looked fine but the gear would spin on the shaft. Now THAT will make you go nuts. If all that checks out, sometimes you have to pack an oil pump with Vaseline so it will 'prime'. That's a must on the 907 Lotus, for instance.
There's another way to prime a new motor: get a 110V electric drill with a socket that will fit on the hex shaft. Take it from me: a rechargeable drill won't do it. You then remove the dizzy, stick the socket on the driveshaft and spin like mad till it starts building oil pressure. Saves a lot of wear and tear on the starter.
I will ask generic questions since I have no knowledge of or interest in English cars:
How many spots can it leak (suck air) on the intake side of the oil pump? Pickup tube to pump, or pickup to block to timing cover to pump?
All gaskets in place, and the right shape? I could tell a story about an MGB pump gasket, but that would just upset me.
Driveshaft in place, and the proper length?
Pump was not installed dry, right?
Prelubed by drill, turning the correct direction?
Pickup not jammed solidly against the bottom of the pan?
Pressure relief valve is in place, and not jammed open?
One of our theories is that the distributor isn't turning the gear so I will check that out. The pump was primed when I put it in. I guess my next step is to take off the distributor (which is a colossal pain on the Stag) and prime it like you guys said with the drill.
Sidebar comment about synthetic oils not letting rings seat, a whole lot of factory Corvettes would disagree with that.
If the pump was primed why is filter dry? Did you fill the filter before spinning it on? How was the pump primed? was it hand packed with engine grease or was it simply installed and spun with a drill?
Those darn #2 pencil shaft suck get the motorsport one that a 3/8 round shaft with hardened insert.
One other thing to look at is the pressure regulator. If it's stuck open, then no pressure for you. Stags are nice cars, terrible motors, but nice cars still the same. I have a complete stuck motor sitting on my trailer if you need anything.
The use of RTV anywhere in the crankcase is a no-no generally.
20W-50 oil ? Seems pretty heavy to me.
Thin oil circulates quicker.
Your "mechanic" needs to get up todate.
Thank you every one. I got oil pressure built up tonight! 
Found out that the rod that connects the oil pump and the distributor wasn't connected correctly, the end at the distributor wasn't seating correctly. Hopefully will have a running engine very very soon.
-Thanks again Ryan
