When I first got a bone stock '72 340 Challenger, I ran the heck out of it. Almost got banned from driving it to school because of the burnouts, fast driving, etc. at school and the neighborhood. I went through 3 727's in a year. After my transmission guy finally put a shift kit in, it lasted.
A 727 is "physically" stronger than a 904, but a shift kit will help any trans live longer because it minimizes clutch/band slippage and heat. I was abusing mine to the point that it needed help over stock. My current race car has a 904 and they last for years.
