EA 81 head cracks & reuse

I had an old post months ago about the cracks in my heads and several of you said put them back on, its very common. My salvage motor has head gasket failure, warpage on the head and spark plug hole has stripped threads. If my old heads don't need to be machined would I be able to just slap them on?  I don't know where the bubbles in cooling system in my old motor were coming from, but I assumed the head cracks. 

I would replace the valve seals on the cracked head.

Thanks