To change block position you just use Left, Top, Width and Height properties.
Setting a block position based on another one should be as simple as copying the properties:
Block1.Left := Block2.Left;
Block1.Top := Block2.Top;
Block1.Width := Block2.Width;
Block1.Height := Block2.Height;
if you are experiencing issues with it, it might be something specific, can you post some code?