Does the oil flow through one side of the engine to the lifters and then throught the back of the engine and into the other side or is it they get oil at the same time.
I was having oil pressure problems and took the engine apart (not completely) and didn't find anything that could be the cause. And now when I use the oil primer to turn the oil pump only one side gets oil to the lifters.

 

The system is a little like this:

 

Thanks thats the help I was looking for.

 

The one thing not shown in that pic, is that the distributor housing goes RIGHT THROUGH the oil passage to the pass side lifters. Look at the dist gear on the cam, and how the passage goes into the paper and then turns left to go toward the front, right above the dist gear; the dist housing intersects that passage right above the dist gear as you can see it in that pic. Without a dist housing in the engine, or at least something to simulate one, there will be a massive internal pressurized oil system leak right behind the #8 exhaust lifter bore.