I used to street race in the Detroit area late 70's thru mid 90's. Way big difference in the 904 than the 727. Cost more but way more bang for the buck. The best guy in doing the 904 is Joel's on Joy in South Lyon,Mich. I picked up a second faster by going to his 904 than his 727. He builds the best of both. That is why all the super stock SS/AA guys use his trans. Way more torque and less H.P. loss with the 904. There was a major difference in the way my car left the line and launched harder with the 904. With a small block to this day I use his 904.