Keith Craft once explained that the FE engines were designed for rope seal on the back of the crankshaft. As such, there was no need for precision machining back in the day, but today's seals require the gland to be more centered than what the factor did. Hence the FE reputation for marking its territory. So yes a factory block FE is more likely to drip some
oil out the rear main seal. And let's skip talking about the nails in the seal between the rear main cap and the block.
If I recall correctly Keith said he had tried and gave much thought to the problem and even he could not achieve 100% leak free FE engines. I have heard others state if anyone tells you they can, stay away from them cause they are either an idiot or a lyre.
Now if you us a modern new block, I would expect the rear seal issue have improve dramatically, but I have no personal experience.
The FE is a very complicated design compared to a SB. When assemble by a knowledgeable experienced FE builder, it is a great engine. When assembled by other builders with little FE experience, your asking for trouble. That can be said to be true for any engine, but the less complicated the design the better chances are any builder can do it.
So the answer, in my opinion, depends on who is building what.