ProComp/Speedmaster aluminum heads

You are going to have to look at the retainers that fit your spring diameter....the retainers I use 1.40 ..I use with a 1.46 spring....they wont work with your spring.
So going off spring diameters and the retainer diameters, they have two different styles that would work for my springs. A flat retainer and a dished retainer.
1.250" Od. 0.870" Id. 7 Degree 11/32 Flat Chromoly Steel Valve Spring Retainers

1.250" Od. 0.870" Id. 7 Degree 11/32 Dish Chromoly Steel Valve Spring Retainers