[Mg-t] Engine cleaning - need Help

[PopeyMike at aol.com]

Have had to pull XPAG engine out of my 53 TD
 
Cylinder head rebuilt formerly by a real amateur - used different diameter  
valves in every cylinder.  Found this because the head gasket gave out and  
water got in oil.
 
Now to clean the engine block water passages & seperately oil passages  
need your collective advise.
 
Is it wise to use phosphoric acid in the water galleys?  Does it have  to 
be neutralized afterwards and with what solution?  Or is it enough just  to 
massively flush out the acid?
 
Is it better to use a caustic solution such as sodium hydroxide (Draino  
crystals) - and does this need to be neutralized or just flushed?
 
I read about some passage way that needs cleaning behind one of the freeze  
plugs - any info on this?
 
How much does the engine weigh?
 
Is it safe to lift it with the head bolts without doing damage to the head  
bolts?