"keep the 904"
Wrong in my experience on 2 counts
1. In this case weren't you pulling a /6? THAT 904 won't bolt up to anything but a /6. Need a different 904.
And 2. Especially when driven in a "performance" fashion the 904 won't hold up -- might do better with being "built up" but I haven't had good luck with 904s in general even when driven like an old person. I've ditched a handful of 904s in favor of 727s for that very reason