Quote: Having had quite a lot of experience with the 4L60e and the 700r4 I can tell you that 600ft-lbs combined with a street radial and the weight of a B-body is nearing the limit for these gearboxes. Having said that, though, if you stay within those limits or you are running 235-275 tires, they are hard to beat. They shift smoothly, have a fairly small profile and in the case of the 4l60e you can program it to shift like a Caddy on light throttle input and slam gears like it has a monster shift kit at high throttle input. Makes it very flexible for mixed use cars. I would not suggest one for a car that goes to the track every weekend, but for street or mixed use they are a good choice.
What would be the next logical step-up if it was going to go in a heavy car and see a little track use? Or if I supercharge the 6.1 and crest the 600lb mark? A built 727 with GV or ?
