There are applications where this will work, I know it fits the small diameter Distributors for Windsors and 289/302.
As mentioned above the Spring Blade in the center of the rotor must make actual contact with the carbon button. I found a good way to check is to put a film of Dielectric grease, assemble the cap onto the distributor and then remove the cap an check the carbon button for indication of grease and the rotor blade for the inpression of the button, adjust the Spring Blade accordingly, then remove the grease.
http://msdignition.com/Products/Dist...tributors.aspx