at what point do you decide if you need a aftermarket housing

have a 63 galaxie with the early style 9" with the big axle bearing ends the center section has the 2 dinples on the back side, i was thinking of welding a competiton engineering back brace on it and calling it good, motor is a 557 with 750 hp same on the torque trans is a c-6 with 4000 stall rearend is going to be 35 spline axles with 4.56 gears and a spool

thanks for the info/advice

rick