[red82gt]

Why not a TKO 600? For the money, it's the stoutest gearbox out there. The Gforce T5 with the upgraded mainshaft is $2500 ($2000 for the basic box plus $499 for the better mainshaft) and you still have the weaker T5 case. I'm going to use a TKO 600 behind my 393.
The richmond 5 speed won't be strong enough (450ft/lb capacity), the richmond ROD 6 speed might be okay. The liberty or a G force 5 speed (not T5) is something like $5000, that's the main reason why only harcore racers have them. Much cheaper to use an automatic.