A factory Slant 6 with a 8 1/4 differential
I had a /6 car with a 8.25 also- in a feather duster of all things. It was a 225-1, 3.09 1st 833od, 2.76sg 8.25 car with discs, front sway bar,white bucket int with console,AM/FM, P/S, P/B, A/C and rally wheels, it also had rocker trim, wheel lip mouldings, driprail trim and a trunk light.
The car really didn't make sense to me since it was loaded out but the Feather Duster/Dart Lite was a lightweight MPG package.