For at least 10 years now the early white plastic pull-offs have been HORRIBLE. The spring in them is too strong requiring nearly 15" engine vacuum to fully apply them. They release INSTANTLY so useless for dampening the secondaries.
I'm been modifying them here but it is not easy. So I decided to enlist some help and I just got back the first batch of modified pull-offs. They are EXCELLENT. Takes 5-6" vacuum to fully apply them and the correct restrictor was added so the release time is perfect, just like the original factory pull-offs.
They are available off the website or you can call the shop to order at 740-397-2921.....