1) Hope your 700R4 holds up (with luck, maybe someone beefed it up), and definitely avoid using slicks.
2) Buy a built one from a reputable shop. The really strong ones are going to be very expensive. Remember most companies will rate them by horsepower level, but it's really torque that kills the transmission, so be sure they know it's a big block, and not a 450hp small block.
3) Switch to a 4L80E or 4L85E. This isn't cheap either, because you need to get a programmable ECU and modify the transmission tunnel.
4) Switch to a TKO600. Of course it's no longer an automatic.
5) Change to a TH400, but then you lose the overdrive.
