ProComp/Speedmaster aluminum heads

How do you know the procomp springs won't work?
I don't..
Earlier in the thread PRH said the ones he had had very low spring rate... Also to have them tested.. I'm going to take this advice on both accounts... I'm actually juggling between his and 70aarcuda's spring recommendations and having a hard time telling the difference if there is any..
Just doing my due diligence and research way ahead of time...