There is that metal filings looking stuff they sell at AutoZone. You can put a tube in and see if the leak is fixed.
If it was a head gasket, you would see in on top of the rear of the block.
Seems like Pat has covered the main bases.
There is also infrared die. That may pinpoint the exact location and save you from pulling the engine.
If it is in the block ( crack ) it will get worse as the block thermally cycles.
Just my opinion.
