What to do gearbox wise with big horsepower

[02PRUV]

New engine will probably make around the 800whp. Should I stick with the T56 and get a clutch that will handle it or just get a built 4l80e. What would others do?

[Tryhard]

Comes down to budget and what are you mainly gonna use the car for,if you want it for street and dyno duties stick with a t56 with a nice twin plate organic clutch like an npc or the like. If you are gonna be doing street and 1/4 mile duties a built 4l80e.

[AVENGE]

Depends how aggressive its gonna be etc. I've driven a Stroked and Blown VU Ute with around 780rwhp and a T56 with a twin plate.....Very aggressive car, but def wouldn't want to be driving it round all day. The owner gives it a pretty hard time and is on his 3rd box.
Have also driven EV1LR8's VZ Clubby which is a 6.0L with a 232/234 cam plus a GT4202 hanging off the side, NPC single plate button clutch, T56, and it actually surprised me how pleasant it was to drive, could drive it round as a daily quite easily and thats a touch under 700rwhp from memory.

[feistl]

Depends if you want auto or manual. I went with a T56 Magnum with 31 spline output shaft, changed ratios, upgraded internals etc. Box cost about $6k, $2k for tailshaft.

All depends if you want to do it cheaply or properly....