Apparently you do not know that the factory cowl braces are bolted on and about a sturdy as a pair of EMT conduit pieces flattened at the ends.

It is NOT a chassis item. Not even close. The aftermarket make have sturdier stuff, but not the musclecar era factory stuff.

They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.