Hi when you do deck height you put the oil rings on number 1 and nunber 4 piston
put the crank in with the bearings front and rear mains put pistons in then use a dial clock measure the center of piston (deck has to be clean) then rotate clock to deck measure ,then do rear piton @TDC,NOW you know if block is on angle, facing is done of sump face so when mount it in machine you clock it in and shim it if need be , rods will play a part if lengths are different ,Having deck @0 is ok you may have to check piston to valve
depending lift and dur & valve size and piston type chapo