Have a T 56 in my 59 Vette, 3:73 rear axle. Love it, wish would simply fit in our Challenger, currently Passon 4 speed equipped, 4:10 axle. Tremec shifting action in all gears is very smooth, positive with a very short throw. Not certain how well would hold up in a 512 big block engine however.

Have 2 pals that are running Passon equipped E Bodies. Both quite pleased with them. One is running a 3:73, the other a 4:10. I've not driven either to Find how well they shift compared to T 56. Am curious as Passon does still use external linkage system.

Also running a hydraulic clutch in the Vette. Kicking myself for not installing same in Challenger last time had engine out. Much easier on the old left leg.