Here goes...My '56 F-100 project is getting a Blown 331 Hemi for power...real mild cam ...5 lbs. boost...set-up for performance but not racing (maybe 400 HP?). I've got a nice Mopar 904 transmission with a 2000 stall converter...just rebuilt...Alot of hot 340's used these 904's and they seemed to work fine. Do any of you transmission experts have an opinion on why I have to use a 727? Hell, I'm using a 9" with 28 spline axles so if I trust the 28 splines I should be OK with the 904...I need an opinion. Thanks.