If the cars have sat that long, then the original oil will may have turned into a gooey mess.
I would not turn it over or attempt to start an engine like this until I'd pulled the oil pan, cleaned out any sludge and other crap in the bottom of it and did the same to the oil pump. You don't want the oil pump to attempt to pull that crap into it and then push it into the bearings - which can ruin them.
Also, don't just drain the oil-pan and throw nice-new detergent oil back in. Modern oils will loosen up any crap that is sitting in the pan and then it all gets pumped through the bearings.
I recently bought a car that had sat since 1959 (indoors). I pulled the pan and you should have seen how the oil had separated into a top-layer of clear gold looking stuff and a bottom layer of thick gunk. This is what non-detergent oil does - and who knows what was last put in these engines.
Also, while I have the pan off, I pull a main cap and a rod cap and give the bearings a good visual inspection - so I have some idea as to the condition of the lower end.
Another thing I do is pull the heads, check the bores, inspect the valves, etc.. If it was sitting for a long time (especially in an un-heated location), then there will probably be rust on the valves/seats that were open. I try to clean everything up, oil the bores, turn it over to make sure no valves are stuck (very common), then put new head gaskets back on it.
All of this is a bit of work, maybe a weekend or so . . . but it is the best way to go about getting engines that have sat for a long time - checked out and ready to run.
Best of luck!
B&S