Syncronizer design has changed a bunch over the past 30 years. It used to be common to have 1 brass syncro ring. Now the syncronizer assembly can have 3 parts with bonded materials to aid slowing the gears to insure smooth shifting.
In making the transmissions smoother shifting they don't take to clutchless shifting very well.
In my opinion it will damage the syncornizer teeth over time.
Holley Performance Products