Minor leak under front head freeze plug. Suggestions?

[cheburashka]

'74 Mercruiser 140. I didn't winterize properly and the block froze. So far I've replaced the freeze plugs and the head, which had a crack in the intake. I've torqued the new head and pressurized the water jacket. I get some leakage from a crack in the usual place, under the manifold and above the freeze plugs. It's a small leak and I plan to do the drill/chamfer/JB weld trick to it. The second leak is very slight, and shows as a slight weeping of water between the head and the block, at the front of the engine right underneath the freeze plug between 1&2 when the block pressure hits 15 lbs. No water appears to be going into the oil. I haven't run the engine yet, so I think it would be OK to remove the head again and check out that area of the block and head for cracks, but I'm wondering if anything else could be causing this, specifically whether I should start the engine and let it heat up so that the head gasket will bed in and release whatever sealant is in it. Should the head gasket seal perfectly when it's cold and it has just been torqued? If I pull the head now, will I need to put on a new head gasket?

Thanks