[olddog]

How many rpm are you building the engine to peak the Hp? Or more precisely, how many rpm will be you shift point? It matters.

The TKO 600 (which I have one), does not shift as good as it should above 6500 rpm. Some say a little less. There are experts who can modify the transmission to shift much better and at much higher rpm. A used TKO sent in to be modified, would give you a better than new unit for about the same price as new. Maybe less, if you get the right deal.

I suspect every transmission out there has something less than ideal, under some conditions. I cannot tell you specifics.

The Tremec six speeds may be a bit too long to fit in some Cobras, especially if a live axle is used.

You might want to expand your knowledge quest into some of these other areas.

Good luck.