Hey, a good built 904 does a good job behind a built small block. The 904 is a little lighter than the 727 and a lot of the street racers are using them because small block 727's are hard to find. The Valvebody an the speedo pinion is the only things I know of that will interchange between the two IF They Are Both NON LOCKUP. Check at a local salvage yard for a 16 passanger van with a 360 and you might find a non lockup 727.