How strong are 8 1/4s

I used to race a 66 cuda and one night in final round street class i went to line reved up green light and snap no go. Built custom 8.75 for racing no more problems ever! Wish I still had it for my current 65 so I could do some racing, need to get one bigger rear so no snap at track.....318 w little over 300 hp mid 14's so be careful with small rear....