I put the old Street Twin in my Road Runner behind a nicely built 440 6 bbl. I put about 4000 miles on it. When I swapped in the Hemi, the assembly looked like new so just bolted it onto the back of the Hemi. The Hemi should have about 600 hp, so I'll see how it holds up. I agree about the comment on the fast shifts. There does seem to be a limit on how fast you can switch gears. I'm sure I can fine tune the shift levers to improve it. But that clutch package is a lot of rotating mass.