Mikey,
Make a replaceable blow off plate, using something like a plastic milk carton for the replaceable media.
I used something like this on my ally plenum on my Nitrous turbo funny bike. If I had a nitrous burp, then the plastic milk carton would blow, leaving the plenum intact, it was good for just under 3 Bar and 3 stages of Nitrous (about 400 HP).
It you make a jig for the blow off plate, then you can easily make replacements at a race meeting. I can see if I still have some pic's if you want.
Seasons greetings
Neil