Safety valve piston type with oil bypass mod

[AndrewSlater]

I have had the oil bypass modification performed on my 1974 2.7 7R case, changed to a Carrera oil pump and have also change the oil pressure relief spring, cap and piston.

However I am unclear as to whether as part of the modification I need to change the style of piston in the safety relief valve.
Wayne Dempseys book seems to show both pistons changed to the new type but I can't understand why I need to change the safety one.

I've read the 'Ultimate Oil Pressure Relief Valve Thread ' on the Pelican website but this too is a little ambiguous.
Somebody asks the same question there but it is not answered.

Does anyone know whether it is OK to use the old style piston ( with holes ) in the safety relief valve when the oil bypass mod has been made?

As always any help would be much appreciated.
Andrew