Years ago when I dealt with Kiesler and thier Tko 600 tranny, it was rated at 600 ft lbs. my engine did not produce that much, but maybe within 40-50 of that. After I broke the tranny, i was told that launching on slicks at the track spiked the shockload above the 600. I got into a nasty brawl with them and they did end up sending me the broken 3rd gear and cluster gear for free. I installed it myself.

I then had the gears faceplated by liberty. I broke the 3rd gear again on the very first pass at the track as well as split the main case. I then went with a jerico.

Point is, i’m not sure what the torque ratings mean if we have no idea of what the shockloads are. A major factor is the clutch. The adjustable slipper type will reduce the shockloads on the shifts.

Just added this info for consideration no matter what trans is used. Good luck.