[wadesdad]

A locked rear end is just that. Both wheels fixed or tied together for better or for worse, in sickness..... It is a set-up I've used in racing, but not good for the street. (the rear wheels fight eachother in turns. Both wheels are turining at the same rate, but on different radius circles in a turn. It typically makes them "chirp" or bind. (A 4x4 in low range will give you the same sensation as you turn).

A "posi-traction (GM?)" or "torque-lock" (Ford) is a limited slip rear-end. With as much power as you intend, you definately need a limited slip rear-end. As one wheel begins to slip, the other joins the traction party. I'm using a torque-lock 9" Ford 3.50:1

Good-luck. I'm in the same winter-build phase as you are.