The 340 is out....again.....
I have only seen a couple of FSM's so can't say if that info for a minimum distance of the pickup from the pan never showed up in later FSM's. But I would presume that 'must touch' means 0.000" maximum distance from pan.....
I kinda question that being a few tenths off the pan floor will cause engine failures, if any at all. For example, the pickup was 1/4" off of the floor of a stock SBM, then the numbers compute out to be less than 1/2 pint of oil that it would not pick up versus being down on the bottom. Maybe in extreme cases.....
Like I said, I saw the numbers in 1980 so I can't remember how far the factory would let the pick up be off the floor of the pan and still let it out the door.
When the pick up gets moved away from the floor on a strainer type pick up like that, it looses its ability to pull oil very quickly. The further away, the quicker it will lose the ability to pull oil. With a stock pan, and a standard 1/4 inch away from the pan with that pick up and you will eat a bearing fairly quick. There are 5 quarts in the system. I always figure 1 in the filter, 1 in each head and 1 in the block and in return. The return number can go up or down, depending on RPM, wind age tray, crank scrapers etc. But that is a fairly close assessment of oil in the system.
You now have 1 quart in the pan and the pick up is 1/4 inch off the floor. Now, stand on the brakes. What little oil that is in the pan is now up in the timing cover and you are sucking air. Seen it happen. Really bad on guys who like to fender race and crap like that.
If you have an aftermarket pan and pick up, you use the distance the manufacturer tells you.
So again, if you are using the stock pan and pick up, the pick up goes down against the pan. The OP's engine builder did that right, and the OP needs to find out what actually happened or he will eat another one.