I believe you will find the 904 tranny will not live long with a lot of strip time you will be stepping up to the 727 larger and stronger internals. Have five years with a 68 Hemi cuda auto not many trans issues even using a 5000 stall 9 inch B&M converter with 4.86's in a 8 3/4" 1.740 pinion sometimes 5.12 at higher altitudes.