I run the TKO 600 behind a warm 496 in a Challenger. It runs on the street and some road track (HSAX). I love it on the street. Driven hard on the track the 2-3 shift is a little tender.

I went with the .81 OD which is a top speed gear with my setup (3.23 rear, ~25" tires, 243@.050" 108 LSA cam). The engine could eaisly carry more overdrive when cruising... double overdrive would be handy in my setup.

On last freshen my engine made 687 ft lb on the dyno so I am pushing the TKO pretty hard.

If I upgrade it will be a T56.