Hump vs transmission and other related questions

[65 wonton]

I have a 66 with, I think, a high hump. It can be seen here on post #18.

I am vasilating between a 4l60 transmission (that came attached to the ls1 from my 98 T/A, which I already have), a T56 or a NV 4500.

Hydraulics doesn't scare me. wiring, cabling, speed-o, crossmember issues are all a wash. I know that I can acquire bolt-up transmissions for the LS! in all 3 models (at least the T-56 and 4l60).

One question is:
1. What are the physical size/footprint differences between the 3 transmissions?
2. Will the firewall and floor take any of these without alteration (no issue with the shifter location for me)?


The LS will not likely go above 500 HP intentionally. The original truck was manual 4 speed. The steering column will be changed (tilt) anyway. 2wd. Daily driver.
A. Is there a difference as far as sturdiness of the transmission for the LS1, power wise?

I know that there will be a question of differences in cost, $600-1400 and driving preferences Stick vs manual and am not asking that.

I just haven't seen these transmissions in real life or side by side to have an idea of fit or experience to know function.

Thanks,

Dave, this should be as easy as 4,5,6.