[SCOTI]

Originally Posted by GlennL

Thanks. I am leaning towards mod'ing the stock unit. No reason to buy something just to cut it up. May as well use what I got and hope I don't need to remove it to get it done.
Thinking about using some flat 1/4" or so by 4" plate shaped as needed and welded in. Then cut the top of the OEM unit out. I think some triangle gussets would help on the sides where you extended it. Surely can't hurt.

Looks like the cab is gonna need a trim as well.

6x-66 cabs have more clearance @ the back of the cab vs. 67-72's so more than likely it will be needed. You also need to make sure about the driveshaft OD for its length to make sure the critical speed crossover point isn't breached.

Also.... Depending on how low it gets & because it has a longer wheel base, the bottom of that x-member might need to be modified as well since it dips lower than the rails @ mid frame.