At 400+hp, What kills A904s?

I honestly probably don't have $500 in my 904 not including converter and like said before it gets beat on and has been in the car untouched for 10 plus years behind a 408 stroker. Works for me that's all I care about. Only thing I own that has a 727 is my 340 swinger if it wasn't a numbers car it would have a 904 also.