The differential is going to be a limited slip Getrag unit that I pulled from a 2010 Challenger SRT8 I parted out. The Challengers with the 6 speed manual transmission received a 3.91 ratio vs the 3.06 that came with the automatic. My 2010 Challenger daily driver has the exact same 6.1L, 6 speed, and Getrag 3.91. With the .50 overdrive ratio, I am turning 2,000 RPM at 85mph. Should be fun off the line and still comfortable on the highway. The differential just got installed so that exhaust could be routed.

View from the right side...

View from behind:

1970 Barracuda B5 6.1 Hemi/6 speed
1969 Charger survivor in R6 383/727-wrecked 12/24/18
1968 Charger in original burgundy paint "Ribeye"
1968 Charger w/ 6.1L, TR-6060, 9"
1968 Charger...clean slate in epoxy
1968 Roadrunner w/ 6.1L/6 speed
2010 B5 Challenger SRT 6.1L/6 speed
2011 Dodge Ram w/ 6.7L