Building a dependable/streetable rear end

[StangLou]

Heres the situation. I would like to go ahead and stick a set of gears in my auto 5.0. Current mods are pulley's, k&n filtercharger kit, Cobra upper and Lower intake that Im installing now, and a MAC 70mm tb.
Heres the catch I would like to keep the gears that I install now when I get my built 331 w/blower installed. This will be in another couple of years, but if at all possible I would like to not worry about gearing.
I was leaning towards 3.90's with a 2400 stall convertor. Will the 3.90's be to much once the blower goes on? Also, should I go on with a 3000 stall since I plan to do the motor/blower later, or will the 3000 be to much for street use.
Finally what would be the best differential to stick in, Ive heard a few bad things about Auburns breaking in Modulars, but Ive always heard good things with 5.0's. Should I go with an Auburn or is there a better one out there.
Thanks for any help in advance!!!

 

[Henceforward]

I have heard good things about Richmond, or FMS (FRPP)

 

[StangLou]

Ive heard good things about Richmond too. Does Motive make a diff or just do gears??? Anyone out there running 3.90's with a blower??? Do ya like them???

 

[Hissing Cobra]

The 3.90's may be a bit much for the supercharger. Once under boost, the supercharger will increase the torque dramatically, which means you won't need as much gear to get it out of the hole. I know that naturally aspirated automatic equipped cars run great with 3.90's-4.10's, while I've seen a lot of supercharged cars running 3.55's-3.73's.

I can't give you advice on the converter's stall speed.

As for the rear end, why not use a Detroil Locker No-Slip unit? I have one of these and it's awesome. It's not a full spool, nor is it a standard issue positraction. It's a spool when going in a straight line, but ratches while cornering. The reliablility is rock solid and there's no clutches to wear out.

 

[StangLou]

Detroil Locker No-Slip unit

Thats a good idea, didnt think of that one

I guess Ill go with the 3.73's with this one as well. I guess I wanted the 3.90's for a bit extra romp around town

Anyone else wanna chime in on the stall speed?