Novi 100 bracket flex

PITA...... I have a novi 1000 2 belt setup with an 8 inch crank pulley and what i guess is a stock pulley on the head unit ( i have a smaller backup that came with my used kit as well) Makes 10# of boost. When you tension the belt you can clearly see the bracket flex. On the hwy all is well but at the track if you hit the rev limiter 6250 rpm (fox mustang) it will dump both belts. I'm sure this is old news to most but I am trying to make a sort of tensioner to stiffen up the mount setup of the blower. I don't run solid motor mounts so i dont want to tie it into the strut tower and risk breaking something under load. I will post pics when it is done unless you post some first so I can get an idea of what to do.

Do you still have the stock balancer on? I've noticed with mine it would throw both belts until i replaced the balancer, it's just a possibility with an old balancer..