I welded up the thingy in my 318 distributor, and observed results like the chart says.

In fact, originally, the stock heavy spring was heavy enough, it was acting as an advance limiter (I never go over 3k; work truck).

If you take out the vac advance and weld that plate in place, you'll lose any advance from the vacuum. You'll still have mechanical advance.

The only benefit to doing this would be to keep the plate from jittering around and bouncing the timing. Or, if it's solely a race engine. For the street, I'd tune it so it works