[D13]

Cast iron 2wd? Because I've not seen that in GM. All the 2wd ones I've seen are aluminum and 4wd cast iron.
I personally believe that the 4wd shifter sits slightly left to make room for the t-case shifter. Some day I'll go thru my pile o parts and prove / disprove. The Competition Plus note above it that people are taking the regular pattern Hurst A-833 Mopar shifter and modding it for the OD trans.

You may have a Dodge trans. Does it have the same input / output shaft splines and lengths? Or maybe just a Dodge shifter....
I've toyed with swapping my 2wd guts into my CI 4wd case, just to eliminate the housing bore wear issue.

And as I thought about it I suspect your trans hump is narrower than the later trucks. The high hump version of those were set up to accept any trans and with the transfer case package.