At what point are anti-balloon plate needed?

balloon plates are left over from the days that you had to modify a stock convertor core to build a racing converter. Majority of converters today are built from billet components and they are strong enough that balloon plates are not needed.

Anti ballooning plates are/were result of the invention of the Trans brake

So, about 600 HP 505" stroker in a 4,000+ lb car with 3.23:1 gears.
I worry a stock high stall converter will balloon.
Which aftermarket converters would be safe from ballooning that don't have the plates?

Really seems like a question for whichever converter company you decide to go with, and what configuration they intend to build for you.

Why not just make sure there is an Anti ballooning plate on whatever converter you are buying...problem solved.

With a short gear like that - that plate would be advisable. Check with your converter supplier.

My old converter was a Dynamic 10" race converter with the single anti-balloon plate, and my current converter is an Ultimate 9" with dual anti-balloon plates.
I used these converters several years ago.

I'll call Lenny at ultimate and ask what he suggests, but I think he will recommend the anti-ballooning plate?