-31 is actually the last digits of a part number on a oem type acctuator.
but the ratings of the springs for boost on these will handle over 20psi happily.
MSD recommend 10psi on the actuator and bleed a further 10psi.
i've got my collins one set to hold 12.5psi, peak at 14.
then i bleed the rest off with an electronic boost controller (gizzmo IBC MS2)