[FredG]

I have the TKO 600 in my Backdraft with a 550 HP Roush engine because that's what it came with. It's adequate. The only time I ever get into the 5th gear is on the highway. The M-21 Muncie I had in the 60's with a Hurst Comp plus shifter was a much better shifting unit. I wish this unit shifted like it. I wouldn't even attempt a full blown, pedal to the floor, power shift with the 600.Speed shifts only. The Muncie had shorter, tighter and smoother throws but I don't know how it would be handling this much HP. I am not that familiar with the toploader thinking it was Fords version of the Muncie. If what you are considering is an older rebuilt transmission my only concern would be where it came from and what was in it.

Fred