Well the power valve adds extra fuel when the vacuum falls below the rating of the power valve.
This is done so you can run a leaner main jet yet not suffer any detonation or any other problems from a lean mixture when under power.
I am not confident that the power valve blowout protection will stop all damage to the power valve and especially when several good backfires take place. They are cheap and easily replaceable so I would suggest just changing it out.
Usually the power valve rating is determined by having the vehicle at idle and in gear (With the parking brake on) and select a valve that is 2" lower than the current vacuum reading. If you have a short duration cam that builds alot of low RPM power the vacuum will be somewhat high and you won't be able to find a valve with a rating that high.
For instance on my truck it idles in gear at 16" vacuum and I will be putting a 9.5 power valve in as that is where my carb goes lean when accelerating from a cruise mode.
There I outwinded you!